Contents Chapter 1: Working inside your computer..................6 Safety instructions................................6 Before working inside your computer........................6 Electrostatic discharge—ESD protection........................7 ESD field service kit ..............................7 Transporting sensitive components.......................... 8 After working inside your computer..........................9 Chapter 2: Removing and installing components................10 Recommended tools................................10 Screw list.....................................
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Installing the coin-cell battery..........................38 Wireless card..................................39 Removing the wireless card............................39 Installing the wireless card............................40 Camera assembly................................42 Removing the camera assembly..........................42 Installing the camera assembly..........................43 Bottom cover..................................44 Removing the bottom cover............................. 44 Installing the bottom cover............................45 Power-supply unit................................
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Updating the BIOS in Windows ............................ 98 Updating BIOS on systems with BitLocker enabled................... 99 Updating your system BIOS using a USB flash drive..................99 Updating the Dell BIOS in Linux and Ubuntu environments..................100 System and setup password............................100 Assigning a system setup password........................100 Deleting or changing an existing system setup password................
You should only perform troubleshooting and repairs as authorized or directed by the Dell technical assistance team. Damage due to servicing that is not authorized by Dell is not covered by your warranty. See the safety instructions that shipped with the product or at www.dell.com/regulatory_compliance.
ESD protection is an increasing concern. Due to the increased density of semiconductors used in recent Dell products, the sensitivity to static damage is now higher than in previous Dell products. For this reason, some previously approved methods of handling parts are no longer applicable.
It is recommended that all field service technicians use the traditional wired ESD grounding wrist strap and protective anti-static mat at all times when servicing Dell products. In addition, it is critical that technicians keep sensitive parts separate from all insulator parts while performing service and that they use anti-static bags for transporting sensitive components.
After working inside your computer About this task CAUTION: Leaving stray or loose screws inside your computer may severely damage your computer. Steps 1. Replace all screws and ensure that no stray screws remain inside your computer. 2. Connect any external devices, peripherals, or cables you removed before working on your computer. 3.
Some systems have magnetic surfaces. Ensure that the screws are not left attached to such surface when replacing a component. NOTE: Screw color may vary with the configuration ordered. Table 1. OptiPlex 7490 All-in-One screw list Component Screw type Quantity Screw image Cable cover—optional...
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Table 1. OptiPlex 7490 All-in-One screw list (continued) Component Screw type Quantity Screw image Camera assembly M3x5 Camera door M3x5 Heat sink—UMA Captive screws Heat sink—Discrete Captive screws Power-supply unit (PSU) M3x5 PSU fan M3x5 Rear-I/O bracket M3x5 System board...
Before working inside your computer. CAUTION: When servicing the system, place it on an elevated, clean, and flat surface. Dell Technologies recommends removing the stand to avoid accidental damage to the system display during servicing. About this task The following image provides a visual representation of the fixed stand removal procedure.
Installing the fixed stand Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure. About this task The following image provides a visual representation of the fixed stand installation procedure. Steps Align and insert the hooks on the mounting bracket on the stand into the slots on the monitor, until you hear a click. Next steps 1.
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About this task The following image provides a visual representation of the articulating stand removal procedure. Removing and installing components...
Steps 1. Press and slide the release button up. 2. Hold the button in the release position, and lift the stand upward. 3. Slide the stand downward, to lift the stand off the back cover. 4. Pry the rubber feet from the bottom cover and pull it out. Installing the articulating stand Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure.
Before working inside your computer. CAUTION: When servicing the system, place it on an elevated, clean, and flat surface. Dell recommends removing the stand to avoid accidental damage to the system display during servicing. About this task The following image provides a visual representation of the height adjustable stand removal procedure.
Steps 1. Press and slide the release button up. 2. Hold the button in the release position, and lift the stand upward. 3. Slide the stand downward, to lift the stand off the back cover. Installing the height adjustable stand Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure.
Steps 1. Align the tabs on the stand with the slots on the back cover. 2. Slide the stand upward until it clicks into place. Next steps 1. Follow the procedure in After working inside your computer. Cable cover—optional Removing the cable cover Prerequisites 1.
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Steps 1. Unroute the power cable from the slots on the cable cover. 2. Remove the screw (M3x9) that secures the cable cover to the bottom cover. 3. Lift the cable cover from the bottom cover. Removing and installing components...
Installing the cable cover Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure. About this task The following image provides a visual representation of the cable cover installation procedure: Removing and installing components...
Steps 1. Route the power cable through the slots on the cable cover. 2. Align the screw hole on the cable cover with the screw hole on the bottom cover. 3. Replace the screw (M3x9) to secure the cable cover to the bottom cover. Next steps 1.
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Steps 1. Press and hold the release tab on the back cover to release it from the latch on the system-board shield. 2. Slide the back cover up to release the tabs on the cover from the slots on the middle frame. 3.
Installing the back cover Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure. About this task The following image provides a visual representation of the back cover installation procedure. Removing and installing components...
Steps 1. Place the back cover on the middle frame and system-board shield and align the tabs on the back cover with the slots on the middle frame. 2. Slide the back cover to lock the release tab under the latch on the system-board shield. Next steps 1.
Steps 1. Press down the tab securing the hard-drive assembly to the system-board shield. 2. Slide and lift the hard-drive assembly from the slot on the display-assembly base. 3. Pry the tabs on hard-drive bracket from its slots on the hard drive. 4.
Steps 1. Align the tabs on the hard-drive bracket with the slots on the hard drive. 2. Flex the hard-drive bracket and replace the remaining tabs on the hard-drive bracket with the slots on the hard drive. 3. Place the hard-drive assembly into the slot and slide it to lock the hard-drive assembly on the display-assembly base. Next steps 1.
Steps 1. Pry and remove the DIMM door from the system-board shield. 2. Using your fingertips, spread apart the securing clips on the memory-module slot until the memory module pops up. 3. Slide and remove the memory module from the memory-module slot. NOTE: Repeat step 2 and 3 if there are two memory modules.
Steps 1. Align the notch on the memory module with the tab on the memory-module slot. 2. Slide the memory module firmly into the slot at an angle and press the memory module down until it clicks into place. NOTE: If you do not hear the click, remove the memory module and reinstall it.
Steps 1. Remove the five screws (M3x5) that secure the system-board shield to the display-assembly base. 2. Lift the system-board shield off the display-assembly base. Installing the system-board shield Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure. About this task The following image indicates the location of the system-board shield and provides a visual representation of the installation procedure.
Steps 1. Align the screw holes on the system-board shield with the screw holes on the display-assembly base. 2. Replace the five screws (M3x5) to secure the system-board shield to the display-assembly base. Next steps 1. Install the back cover. 2.
About this task The following image indicates the location of the M.2 2230 solid-state drive and provides a visual representation of the removal procedure. Steps 1. Remove the screw (M2x2.5) that secures the solid-state drive to the system board. 2. Slide and remove the solid-state drive from the M.2 card slot on the system board. Installing the M.2 2230 solid-state drive Prerequisites CAUTION:...
Steps 1. Align the notch on the solid-state drive with the tab on the M.2 card slot. 2. Slide the solid-state drive into the M.2 card slot on the system board. 3. Replace the screw (M2x2.5) to secure the solid-state drive to the system board. Next steps 1.
Steps 1. Remove the screw (M2x2.5) that secures the solid-state drive to the system board. 2. Slide and remove the solid-state drive from the M.2 card slot on the system board. Installing the M.2 2280 solid-state drive/Intel Optane memory module Prerequisites CAUTION: Solid-state drives are fragile.
Steps 1. Align the notch on the solid-state drive with the tab on the M.2 card slot. 2. Slide the solid-state drive into the M.2 card slot on the system board. 3. Replace the screw (M2x2.5) to secure the solid-state drive to the system board. Next steps 1.
Steps 1. Disconnect the system-fan cable from the system board. 2. Remove the three screws (M3x5) that secure the system fan to the display-assembly base. 3. Lift the system fan, along with its cable, off the display-assembly base. Installing the system fan Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure.
Steps 1. Align the screw holes on the system fan with the screw holes on the display-assembly base. 2. Replace the three screws (M3x5) to secure the system fan to the display-assembly base. 3. Connect the system-fan cable to the connector on the system board. Next steps 1.
Steps 1. Using the plastic scribe, press on the metal clip to release the coin-cell battery from the coin-cell battery holder. 2. Lift the coin-cell battery from the coin-cell battery holder. Installing the coin-cell battery Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure. About this task The following image indicates the location of the coin-cell battery and provides a visual representation of the installation procedure.
Steps With the positive-side facing up, insert the coin-cell battery into the battery holder on the system board and gently press the battery until it snaps into place. Next steps 1. Install the system-board shield. 2. Install the back cover. 3.
Steps 1. Remove the two screws (M2x2.5) that secure the wireless-card shield to the system board. 2. Unroute the antenna cables from the routing guides on the wireless-card shield. 3. Lift the wireless-card shield out of the system. 4. Remove the screw (M2x2.5) that secures the wireless-card bracket to the wireless card. 5.
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Steps 1. Connect the antenna cables to the wireless card. The following table provides the antenna-cable color scheme: Table 2. Antenna-cable color scheme Connectors on the Antenna-cable color Silkscreen marking wireless card △ (white triangle) Main White MAIN Auxiliary Black ▲...
5. Follow the procedure in After working inside your computer. Camera assembly Removing the camera assembly Prerequisites 1. Follow the procedure in Before working inside your computer. 2. Remove the stand. 3. Remove the cable cover (optional). 4. Remove the back cover.
Steps 1. Remove the two screws (M3x5) that secure the camera-assembly door to the display-assembly base. 2. Disconnect the camera cable from the connector on the system board. 3. Remove the two screws (M3x5) that secure the camera assembly to the middle frame. 4.
2. Slide the camera assembly on the middle frame, and align the screw holes on the camera assembly with the screw holes on the middle frame. 3. Replace the two screws (M3x5) to secure the camera assembly to the middle frame. 4.
Steps 1. Remove the four screws (M3x5) that secure the bottom cover to the display-assembly base. 2. Pry and lift the bottom cover off the display-assembly base. Installing the bottom cover Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure. About this task The following image indicates the location of the bottom cover and provides a visual representation of the installation procedure.
Steps 1. Align the screw holes on the bottom cover with the screw holes on the display-assembly base. 2. Replace the four screws (M3x5) to secure the bottom cover to the display-assembly base. Next steps 1. Install the system-board shield. 2.
Steps 1. Remove the screw (M3x5) that secures the power-supply socket to the rear-I/O bracket. 2. Slide the power-supply socket out of the rear-I/O bracket. 3. Remove the power-supply cable from the routing guides on the rear-I/O bracket and PSU fan. 4.
Steps 1. Align and place the PSU in the slot on the display-assembly base. 2. Replace the screw (M3x5) to secure the PSU to the display-assembly base. 3. Connect the power-supply cable to the connector on the system board. 4. Route the power-supply cable through the routing guides on the rear-I/O bracket and PSU fan. 5.
Steps 1. Remove the power-supply cable from the routing guides on the PSU fan. 2. Disconnect the PSU-fan cable from the system board. 3. Remove the two screws (M3x5) that secure the PSU fan to the display-assembly base. 4. Lift the PSU fan from the display-assembly base. Installing the PSU fan Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure.
Steps 1. Align the screw holes on the PSU fan with the screw holes on the display-assembly base. 2. Replace the two screws (M3x5) to secure the PSU fan to the display-assembly base. 3. Connect the PSU-fan cable to the connector on the system board. 4.
About this task The following image indicates the location of the heat sink and provides a visual representation of the heat sink removal procedure. Steps 1. In reverse sequential order (as indicated on the heat sink), loosen the five captive screws that secure the heat sink to the system board and the display-assembly base.
Steps 1. Align the screw holes on the heat sink with the screw holes on the system board and the display-assembly base. 2. In sequential order (as indicated on the heat sink), tighten the five captive screws that secure the heat sink to the system board and display-assembly base.
About this task The following image indicates the location of the heat sink and provides a visual representation of the heat sink removal procedure. Steps 1. In reverse sequential order (as indicated on the heat sink), loosen the nine captive screws that secure the heat sink to the system board and the display-assembly base.
Steps 1. Align the screw holes on the heat sink with the screw holes on the system board and the display-assembly base. 2. In sequential order (as indicated on the heat sink), tighten the nine captive screws to secure the heat sink to the system board and display-assembly base.
6. Remove the heat sink. About this task The following image indicates the location of the processor and provides a visual representation of the removal procedure. Steps 1. Press the release lever down and then push it away from the processor to release it from the securing tab. 2.
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Steps 1. Ensure that the release lever on the processor socket is fully extended in the open position. NOTE: The pin-1 corner of the processor has a triangle that aligns with the triangle on the pin-1 corner on the processor socket.
Rear-I/O bracket Removing the rear-I/O bracket Prerequisites 1. Follow the procedure in Before working inside your computer. 2. Remove the stand. 3. Remove the cable cover (optional). 4. Remove the back cover. 5. Remove the system-board shield. 6. Remove the bottom cover.
Installing the rear-I/O bracket Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure. About this task The following image indicates the location of the rear-I/O bracket and provides a visual representation of the installation procedure.
System board Removing the system board Prerequisites 1. Follow the procedure in Before working inside your computer. NOTE: Your computer’s Service Tag is stored in the system board. You must enter the Service Tag in the BIOS setup program after you replace the system board. NOTE: Replacing the system board removes any changes you have made to the BIOS using the BIOS setup program.
4. Disconnect the PSU fan cable from the connector on the system board. 5. Open the latch and disconnect the power-button board cable from the connector on the system board. 6. Disconnect the speaker cable from the connector on the system board. 7.
10. Connect the speaker cable to the system board. 11. Connect the power-button board cable to the system board and close the latch to secure the cable. 12. Connect the PSU-fan cable to the system board. 13. Connect the PSU cable to the system board. 14.
Steps 1. Disconnect the speaker cable from the connector on the system board. 2. Remove the six screws (M3 4+7.1xZN) that secure the speakers to the display-assembly base. 3. Remove the speaker cable from the routing guides on the display-assembly base. 4.
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Steps 1. Align the screw holes on the speakers with the screw holes on the display-assembly base. 2. Replace the six screws (M3 4+7.1xZN) to secure the speakers to the display-assembly base. 3. Route the speaker cable through the routing guide on display-assembly base and connect the speaker cable to the system board.
Power-button board Removing the power-button board Prerequisites 1. Follow the procedure in Before working inside your computer. 2. Remove the stand. 3. Remove the cable cover (optional). 4. Remove the back cover. 5. Remove the system-board shield. 6. Remove the bottom cover.
Installing the power-button board Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure. About this task The following image indicates the location of the power-button board and provides a visual representation of the power-button board installation procedure.
Microphones Removing the microphones Prerequisites 1. Follow the procedure in Before working inside your computer. 2. Remove the stand. 3. Remove the cable cover (optional). 4. Remove the back cover. 5. Remove the system-board shield. 6. Remove the bottom cover. 7.
Installing the microphones Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure. About this task The following image indicates the location of the microphones and provides a visual representation of the installation procedure. Steps 1.
Side I/O-board Removing the side I/O-board Prerequisites 1. Follow the procedure in Before working inside your computer. 2. Remove the stand. 3. Remove the cable cover (optional). 4. Remove the back cover. 5. Remove the hard drive. 6. Remove the system-board shield.
Steps 1. Remove the two screws (M3x5) that secure the side I/O-board shield to the display-assembly base. 2. Lift and remove the side I/O-board shield off the side I/O-board. 3. Disconnect the SIO-signal cable, SIO-power cable, and audio-board cable from the system board. 4.
Steps 1. Align the screw holes on the side I/O-board with the screw holes on the display-assembly base. 2. Replace the two screws (M2.5x3.5) to secure the side I/O-board to the display-assembly base. 3. Route the SIO-signal cable, SIO-power cable, and audio-board cable through the routing guides on the display-assembly base.
Steps 1. Disconnect the audio-board cable from the connector on the system board. 2. Remove the screw (M3x5) that secure the audio board to the display-assembly base. 3. Lift and remove the audio board with the cable off the display-assembly base. Installing the audio board Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure.
3. Connect the audio-board cable to the system board. Next steps 1. Install the side-I/O board. 2. Install the speakers. 3. Install the rear-I/O bracket. 4. Install the bottom cover. 5. Install the wireless card. 6. Install the system-board shield. 7.
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Steps 1. Remove the antenna cables from the routing guides on the display-assembly base. 2. Remove the two screws (M2x2.5) that secure the antenna modules to the middle frame. 3. Carefully peel the copper foil that secures the antenna cables to the middle frame. 4.
Installing the antenna modules Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure. About this task The following image indicates the location of the antenna modules and provides a visual representation of the antenna modules installation procedure.
Steps 1. Align and place the antenna modules in the slots on the middle frame. 2. Adhere the copper foil that secures the antenna cables to the middle frame. 3. Replace the two screws (M2x2.5) to secure the antenna modules to the middle frame. 4.
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11. Remove the system board. 12. Remove the PSU. 13. Remove the fan. About this task The following image indicates the location of the display panel and provides a visual representation of the display panel removal procedure. Removing and installing components...
Steps 1. Remove the 12 screws (M3x5) that secure the display panel to the middle frame and display-assembly base. 2. Unroute the display back-light cable from the routing guides on the display-assembly base. 3. Place the system in an upright position. 4.
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Steps 1. Place the system in an upright position, and slide the display panel on the slots of the display-assembly base. 2. Route the display-backlight, and display cable through the slots on the display-assembly base. 3. Place the display-assembly base on a clean and flat surface with the display panel facing down. Removing and installing components...
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4. Replace the nine screws (M3x5) to secure the display panel to the middle frame and display-assembly base. 5. Remove the three jig screws from the display panel and replace with three screws (M3x5) to secure the display panel to the middle frame and display assembly base.
6. Route the display back-light cable in the routing guides on the display-assembly base. Next steps 1. Install the fan. 2. Install the PSU. 3. Install the system board. 4. Install the camera assembly. 5. Install the speakers. 6. Install the rear-I/O bracket.
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Steps 1. Remove the 17 screws (M3x5) that secure the middle frame to the display-assembly base. 2. Remove the middle frame and lift the middle frame off the display-assembly base. Removing and installing components...
Installing the middle frame Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure. About this task The following image indicates the location of the middle frame and provides a visual representation of the middle frame installation procedure.
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Steps 1. Slide and align the middle frame to the slots on the display-assembly base, then snap the middle frame into place on the display-assembly base. 2. Replace the 17 screws (M3x5) to secure the middle frame to the display-assembly base. Next steps 1.
Drivers and downloads When troubleshooting, downloading or installing drivers it is recommended that you read the Dell Knowledge Based article, Drivers and Downloads FAQ SLN128938. Drivers and downloads...
Boot Sequence allows you to bypass the System Setup–defined boot device order and boot directly to a specific device (for example: optical drive or hard drive). During the Power-on Self-Test (POST), when the Dell logo appears, you can: ● Access System Setup by pressing F2 key ●...
NOTE: Depending on your computer and its installed devices, the items listed in this section may or may not appear. Table 4. System setup options—System information menu Overview OptiPlex 7490 All-in-One BIOS Version Displays the BIOS version number. Service Tag Displays the Service Tag of the computer.
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Table 4. System setup options—System information menu (continued) Overview DIMM_SLOT 2 Displays the DIMM 2 memory size. Devices Information Panel Type Displays the Panel Type of the computer. Video Controller Displays the video controller type of the computer. Video Memory Displays the video memory information of the computer.
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Table 6. System setup options—Integrated Devices menu (continued) Integrated Devices Enable Audio Enable or disable the integrated audio controller. By default, all the options are enabled. USB Configuration ● Enable or disable booting from USB mass storage devices through the boot sequence or boot menu.
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Table 8. System setup options—Display menu Display OSD Button Management Disable OSD Buttons Enable or disable the OSD (On-Screen Display) buttons on the computer. Full Screen Logo Enable or disable full screen logo. By default, the option is not enabled. Table 9.
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Table 10. System setup options—Power menu (continued) Power By default, the Enabled in S4 and S5 option is enabled. Fan Control Override Enable or disable the fan control override feature. By default, the option is disabled. Intel Speed Shift Technology Enable or disable the Intel speed shift technology support.
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Allow Non-Admin PSID Revert Enable Allow Non-Admin PSID Revert Controls access to the Physical Security ID (PSID) revert of NVMe hard-drives from the Dell Security Manager prompt. By default, the option is disabled. Table 13. System setup options—Update, Recovery menu...
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By default, the option is enabled. Dell Auto OS Recovery Threshold Controls the automatic boot flow for SupportAssist System Resolution Console and for Dell OS Recovery Tool. By default, the threshold value is set to 2. Table 14. System setup options—System Management menu...
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Table 15. System setup options—Keyboard menu Keyboard Keyboard Errors Enable Keyboard Error Detection Enable or disable the keyboard error detection. By default, the option is enabled. Numlock LED Enable Numlock LED Enable or disable Numlock LED. By default, the option is enabled. Table 16.
If BitLocker is enabled, it must be suspended before updating the system BIOS, and then re-enabled after the BIOS update is completed. Steps 1. Restart the computer. 2. Go to www.dell.com/support. ● Enter the Service Tag or Express Service Code and click Search. ● Click Drivers & Downloads. ● Click Detect Drivers and follow the on-screen instructions.
3. Insert the USB flash drive into the computer that requires the BIOS update. 4. Restart the computer and press F12 when the Dell logo appears to display the One Time Boot Menu. 5. Using arrow keys, select USB Storage Device and press Enter.
Updating the Dell BIOS in Linux and Ubuntu environments If you want to update the system BIOS in a Linux environment such as Ubuntu, see https://www.dell.com/support/article/ sln171755/. System and setup password Table 20. System and setup password Password type Description System password Password that you must enter to log in to your system.
Clearing BIOS (System Setup) and System passwords About this task To clear the system or BIOS passwords, contact Dell technical support as described at www.dell.com/contactdell. NOTE: For information on how to reset Windows or application passwords, refer to the documentation accompanying Windows or your application.
Running the SupportAssist Pre-Boot System Performance Check Steps 1. Turn on your computer. 2. As the computer boots, press the F12 key as the Dell logo appears. 3. On the boot menu screen, select the Diagnostics option. 4. Click the arrow at the bottom left corner.
Diagnostics Power status indicator light: Indicates the power status. Solid amber—The system is unable to boot to the operating system. This indicates that the power supply or another device in the system is failing. Blinking white—The system is unable to boot to the operating system. This indicates that the power supply is normal but another device in the system is failing or not installed properly.
It enables you to diagnose hardware issues, repair your computer, back up your files, or restore your computer to its factory state. You can also download it from the Dell Support website to troubleshoot and fix your computer when it fails to boot into their primary operating system due to software or hardware failures.
Steps 1. Turn on your computer. 2. Go to www.dell.com/support. 3. Click Product support, enter the Service Tag of your computer, and then click Search. NOTE: If you do not have the Service Tag, use the product ID or manually browse for your computer model.
Getting help and contacting Dell Self-help resources You can get information and help on Dell products and services using these self-help resources: Table 22. Self-help resources Self-help resources Resource location Information about Dell products and services www.dell.com Tips Contact Support In Windows search, type Contact Support, and press Enter.
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