Computers · Repair guide

How to fix a computer that keeps restarting

10 fixes, easiest first4 min readUpdated November 2026

Quick fix

If Windows still starts, install updates and check Reliability Monitor for the crash behind each restart. If it is stuck in a loop, open the recovery screen and use Startup Repair or Uninstall Updates.

What it means

A PC that restarts on its own is usually recovering from a crash (a stop code error), losing power for a moment, overheating, or finishing a Windows update. A restart loop, where it never reaches the desktop, usually means a bad update, driver or startup file is stopping Windows from loading.

Common causes

  • A crash (stop code error) that makes Windows restart automatically
  • A Windows update that installs and restarts, or a bad update or driver
  • Overheating that triggers a safety shutdown
  • A loose power cable, failing power supply or weak laptop battery
  • New hardware or a USB device that conflicts with Windows
  • Damaged system files or a startup problem causing a boot loop
  • Failing memory or another hardware fault

How to fix it

Work down the list. Each fix is safe to try before moving on to the next.

01Rule out Windows Update restartsEasy

  1. Open Settings > Windows Update and see whether updates are waiting to finish; install them and restart once.
  2. To stop surprise update restarts while you work, go to Settings > Windows Update > Advanced options > Active hours and set the hours you use the PC.
  3. On Windows 10: use Settings > Update & Security > Windows Update.
  4. If restarts happen only right after updates, the PC may be fine; if they happen at random, keep going.

Why it helps: Planned update restarts are normal and are easy to tell apart from crash restarts.

02Check the power cable and unplug new devicesEasy

  1. Desktop: push the power cable in firmly at the PC and the wall, and plug straight into a wall outlet instead of a power strip.
  2. Laptop: check the charger connection and try the laptop on battery and on the charger to see whether either one changes things.
  3. Unplug any device or hardware you added just before the restarts began, such as a dock, USB drive or new card.
  4. Use the PC for a while and see whether the restarts stop.

Why it helps: A brief loss of power or a faulty new device can make the PC restart without warning.

03Find the cause in Reliability MonitorEasy

  1. Select Search, type reliability and open View reliability history.
  2. Look for red error icons on the days the PC restarted.
  3. Select a day and look for entries such as Windows was not properly shut down or a hardware error, and note any app or driver named.
  4. If the same driver or app keeps appearing, update or remove it.

Why it helps: It shows whether each restart was a crash, a power loss or an update, which points to the right fix.

04Turn off automatic restart to read the stop codeMedium

  1. Select Search, type View advanced system settings and open it.
  2. On the Advanced tab, under Startup and Recovery, select Settings.
  3. Under System failure, clear Automatically restart, then select OK.
  4. Next time Windows crashes it will stay on the error screen. Write down the stop code shown, such as MEMORY_MANAGEMENT, and see the blue screen guide.

Why it helps: Without this, Windows restarts before you can see the stop code that names the problem.

05Check for overheatingEasy

  1. Feel whether the PC is very hot or the fans are loud just before it restarts.
  2. Make sure air vents are clear, and keep laptops on a hard flat surface rather than a bed or sofa.
  3. Move desktops out of tight cabinets and away from heaters or direct sun.
  4. If restarts happen mainly during games or video editing, heat is a likely cause.

Why it helps: PCs switch themselves off to protect parts when they get too hot.

06If it started after an update or new app, undo itMedium

  1. Back up important files first.
  2. New app or driver: uninstall it from Settings > Apps > Installed apps, select More options (...) and choose Uninstall.
  3. Windows update: go to Settings > Windows Update > Update history > Uninstall updates, select the newest update and choose Uninstall.
  4. On Windows 10: use Settings > Update & Security > Windows Update > View update history > Uninstall updates.
  5. Some updates cannot be removed; reinstall security updates once a fix is available.

Why it helps: Restarts that begin right after a change are usually caused by that change.

07Repair system files and test memoryMedium

  1. Select Search, type cmd, right-click Command Prompt and choose Run as administrator.
  2. Type DISM.exe /Online /Cleanup-image /Restorehealth, press Enter and wait for it to finish.
  3. Type sfc /scannow, press Enter and wait until it reaches 100%, then restart.
  4. To test memory, save your work, search for Windows Memory Diagnostic, open it and choose Restart now and check for problems (recommended). After you sign in again, a notification shows the result; it can take a few minutes to appear.

Why it helps: Damaged system files and bad memory are both common causes of crash restarts.

08Escape a restart loop with Startup RepairMedium

  1. If Windows never reaches the desktop, turn the PC on and hold the power button to switch it off before Windows loads. Do this two times.
  2. On the third start, the Automatic Repair screen should appear. Select Advanced options.
  3. Select Troubleshoot > Advanced options > Startup Repair.
  4. If the loop began after an update, choose Troubleshoot > Advanced options > Uninstall Updates instead and remove the latest quality update.
  5. Uninstalling an update keeps your personal files, but some updates cannot be removed. If you have a recent backup, keep it handy before changing anything.
  6. To start in safe mode, choose Troubleshoot > Advanced options > Startup Settings > Restart, then press 4 or F4.

Why it helps: The recovery screen gives you tools to fix or undo what is stopping Windows from starting.

09Run your PC maker's built-in hardware testMedium

  1. If you have a Dell: restart and press F12 repeatedly at the Dell logo, then choose Diagnostics.
  2. If you have an HP: turn the PC off, turn it on and press Esc about once a second, then press F2. Choose System Tests > Fast Test.
  3. If you have a Lenovo ThinkPad: turn it on and press F10 right away to open UEFI Diagnostics. On any Lenovo that still starts Windows, you can instead open the Lenovo Vantage app and choose Hardware scan.
  4. Other brands: check your PC maker's support site for its built-in test.
  5. If a part fails, note the error code or failure ID for the maker's support.

Why it helps: A failing power supply, memory or drive can cause restarts that software fixes cannot solve.

10Roll back with System RestoreAdvanced

  1. Warning: System Restore removes apps, drivers and updates installed after the restore point. Back up your files first if you can.
  2. From Windows: press Windows + R, type rstrui.exe and press Enter.
  3. From a restart loop: on the recovery screen, choose Troubleshoot > Advanced options > System Restore.
  4. Pick a restore point from before the restarts began, select Next, then Finish.
  5. If no restore points are listed, System Restore was not turned on and you cannot use this fix.

Why it helps: It returns Windows system files and settings to a time when the PC was working.

Check it's fixed

  • The PC runs for a full day without restarting on its own.
  • Reliability Monitor shows no new Windows was not properly shut down errors.
  • The PC starts to the desktop normally instead of looping.

When to get help

If the PC still restarts after these fixes, or the maker's hardware test reports a failure, contact the PC maker or a repair shop, since the power supply, memory or motherboard may be failing.

Questions

Why does my computer restart without warning?

Usually Windows hit a serious error and restarted to recover, or the PC lost power or overheated. Turning off automatic restart lets you see the stop code next time.

Why does my PC keep restarting after a Windows update?

The update may still be finishing, or it may not work well with a driver on your PC. Let it finish, then uninstall the latest update if restarts continue.

What does Kernel-Power event 41 mean?

It is an entry in Event Viewer that means Windows restarted without shutting down cleanly. It shows that a crash or power loss happened but not what caused it, so check for stop codes, heat and power problems.

Will a restart loop delete my files?

A restart loop itself does not delete files. Startup Repair and uninstalling updates keep your files, but back up what you can before using System Restore or resetting the PC.

Related fixes

How to fix a blue screen error on WindowsNote the stop code, unplug any new hardware, then install all Windows updates and driver updates. If the crashes began after an update or neHow to fix a computer that is overheatingPut the PC on a hard, flat surface with space around its vents, then open Task Manager with Ctrl + Shift + Esc and close any app using a lotHow to fix a computer that keeps freezingRestart the PC, install all Windows updates, then open Task Manager with Ctrl + Shift + Esc and close or uninstall whatever is using the mosHow to fix a computer that won't turn onPlug the computer straight into a wall outlet you know works, unplug everything else, then drain leftover power by unplugging it (and removiHow to fix Windows Update not installingRestart the PC, make sure you have at least 20 GB of free space, then run the Windows Update troubleshooter from the Get Help app or Setting

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