My computer has been restarting randomly

Diane 0 Reputation points
2026-09-11T15:15:43.3833333+00:00

My Windows 11 has been restarting randomly, brought it to geek squad at best buy , they ran software and hardware scans all good and no problems. they suggested maybe the hdmi ports that I'm using.

since then I have bought a new mouse , keyboard and surge protector. Then i found that I should disable automatic restart and change power start settings. All good for a couple days then there was a software update and it did it again, this time error code kernel security check failure 0 x 139 , it was suggested by a friend to uninstall updates , but then it got into a loop where it would reinstall updates. So I paused the updates and waiting to see what happens. today on the event viewer i saw an error about secure boot failed any suggestions and ideas would sure be appreciated, thanks!

Windows for home | Windows 11 | Windows update
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  1. Diane 0 Reputation points
    2026-09-11T18:20:33.97+00:00

    sounds a little over my head to fix, maybe I should bring it back to the geek squad not unless someone has an easier solution , thanks

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  2. S.Sengupta 32,031 Reputation points MVP Volunteer Moderator
    2026-09-11T15:36:10.72+00:00

    Go to your PC or motherboard manufacturer's support site, find your exact model, and install the latest BIOS/UEFI version. This is the most direct fix for a 'Secure Boot failed' event.

    Enter BIOS/UEFI setup (usually Del or F2 at boot) and look at the Secure Boot section. If it shows an error or 'keys not loaded,' try 'Restore Factory Keys' or toggle Secure Boot off, save, reboot, then re-enable it. This resets the boot signature database that may have gotten corrupted.

    Run Windows Memory Diagnostic.

    Open Command Prompt as Admin and run:

    sfc /scannow' and DISM /Online /Cleanup-Image /RestoreHealth

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  3. AI answer

    2026-09-11T15:16:04.5833333+00:00

    KERNEL_SECURITY_CHECK_FAILURE (0x139) is a stop code error, which means Windows detected a condition that compromised safe system operation and restarted to prevent corruption.

    For random restarts on Windows 11, use this order:

    1. Remove any recently added hardware or peripherals Since the issue is intermittent, disconnect any newly added external devices and test. Unexpected restarts can be caused by hardware devices or their drivers.
    2. Start in Safe Mode If restarts continue, start the PC in Safe Mode and test there. This helps determine whether the cause is a driver or software loaded during normal startup.
    3. Check Device Manager for driver problems
      • Right-click Start > Device Manager
      • Look for any device with an exclamation mark !
      • Right-click that device > Update driver
      • If updating does not help, try Disable device or Uninstall device
    4. Check free disk space Keep 10% to 15% free space available on the drive. Windows and apps need free space for swap files and other operations.
    5. Install Windows updates again after testing Pausing updates can help isolate the issue temporarily, but Windows should be brought back up to date.
      • Go to Start > Settings > Windows Update > Check for updates
    6. Repair Windows system files If the problem started around updates or system instability, run these from Command Prompt as administrator:
      • DISM.exe /Online /Cleanup-image /Restorehealth
      • then sfc /scannow
      Expected result: Command Prompt should report that the restore operation completed successfully, and the SFC scan should reach 100%.
    7. If Windows Update itself is failing, reset the update components Warning: these are administrator command-line steps. Run these commands one at a time in Command Prompt as administrator:
      • net stop bits
      • net stop wuauserv
      • ren %systemroot%\softwaredistribution softwaredistribution.bak
      • ren %systemroot%\system32\catroot2 catroot2.bak
      • net start bits
      • net start wuauserv
      Then restart the PC.
    8. Check the hard drive for errors In Command Prompt as administrator, run:
      • chkdsk /f C:
      Then restart when prompted.
    9. Use recovery options if the issue continues If none of the above helps, restore Windows using a restore point or another recovery option.
    10. If the PC fails to start reliably Restart the PC first. On Windows 11 version 24H2 or later, Quick Machine Recovery can automatically detect repeated boot failures and try to apply a fix from Windows Update if enabled.

    The Secure Boot event in Event Viewer is not enough by itself to identify the cause from the available information. The supported next step is to follow the stop-code troubleshooting path above, especially Safe Mode, Device Manager, system file repair, disk check, and then Windows Update repair if updates are involved.

    References:

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