How to fix a computer that keeps restarting randomly

Summary

This guide helps you troubleshoot and resolve: How to fix a computer that keeps restarting randomly. Follow the steps below to fix the issue.

Common Causes

Random restarts are frustrating and can interrupt important work or risk data loss. On Windows PCs, unexpected reboots are usually caused by one of four things: hardware faults (often heat or power), driver conflicts, Windows Update problems, or failing components such as RAM or storage. This guide walks you through diagnosing each possibility in order, starting with the quickest checks and finishing with deeper troubleshooting.

Quick Fix Steps

If you only have a few minutes, run through these checks first. They resolve the majority of random restart issues.

1. Restart the computer normally and check for pending Windows Updates under Settings > Windows Update. Install anything pending, then choose Restart now if offered.
2. Open Settings > Windows Update > Advanced options and review the recovery options to confirm restart behaviour suits your needs.
3. Check that vents and fans are clear of dust. Feel the air being expelled from the side or rear vents — it should be warm, not hot.
4. Disconnect non-essential USB devices (printers, docks, external drives) and see if the restarts stop.
5. Run the built-in hardware diagnostic by pressing Windows + R, typing msdt.exe -id DeviceDiagnostic, and following the prompts.

Detailed Instructions

Check the Windows Event Viewer for clues

Windows logs the reason for every unexpected restart. Reading the log often pinpoints the cause within a couple of minutes.

1. Right-click Start and choose Event Viewer.
2. Expand Windows Logs and click System.
3. Look for entries with a red error icon around the time of the last restart. Common entries include:
   • Event ID 41 "Kernel-Power" — unexpected restart, often power or hardware related.
   • Event ID 6008 "The previous system shutdown was unexpected" — confirms an unclean shutdown.
   • Event ID 1074 — a process triggered the restart (often a Windows Update or driver).
4. Double-click any matching entry and read the description. Note the BugcheckCode if present — this is a useful search term.

Disable automatic restart on system failure

Stop Windows from rebooting instantly after a crash so you can see any error message that appears.

1. Press Windows + R, type sysdm.cpl, and press Enter.
2. Select the Advanced tab and click Settings under Startup and Recovery.
3. Under System failure, uncheck Automatically restart.
4. Click OK.

Hardware faults

Random restarts that occur during gaming, video calls, or other intensive tasks are commonly heat or power related.

Overheating

1. Open Task Manager with Ctrl + Shift + Esc and click the Performance tab.
2. Watch the CPU and GPU temperatures while the PC is idle. Idle temperatures above 70°C suggest a cooling problem.
3. Shut down, unplug the power, and use compressed air to clean vents and fans. Hold fans still while blowing to prevent over-spinning them.
4. If temperatures remain high, consider repasting the CPU or replacing the thermal pads on a laptop.

Power supply or battery

1. For desktops, try a different wall outlet and confirm the power cable is fully seated at both ends.
2. If the PC restarts only under load, the power supply unit (PSU) may be failing. Test with a known-good PSU if possible.
3. For laptops, remove the charger and run on battery alone. If restarts stop, the charger or charging circuit is suspect.

RAM and storage

1. Press Windows + R, type mdsched.exe, and choose Restart now and check for problems to run the Windows Memory Diagnostic.
2. For a deeper test, download MemTest86 from memtest86.com and boot from the USB it creates.
3. Check storage health by opening a Command Prompt as Administrator and running wmic diskdrive get status. A "Pred Fail" status means the drive is failing and should be replaced.

Driver conflicts

A faulty driver is one of the most common causes of random restarts, especially after a Windows Update or new hardware installation.

1. Right-click Start and choose Device Manager.
2. Look for any device with a yellow exclamation mark. Right-click it and choose Update driver > Search automatically for drivers.
3. If the issue began after a recent driver update, right-click the device, choose Properties, select the Driver tab, and click Roll Back Driver.
4. For graphics cards, download the latest stable driver directly from the manufacturer's website (NVIDIA, AMD, or Intel) rather than relying on Windows Update.

Windows Update issues

Sometimes a Windows Update installs incorrectly and triggers restart loops.

1. Open Settings > Windows Update > Update history and review recently installed updates.
2. If the restarts began right after a specific update, choose Uninstall updates on the same page and remove it.
3. Pause updates for a week by returning to Windows Update and toggling Pause updates.
4. Run the Windows Update troubleshooter: Settings > System > Troubleshoot > Other troubleshooters > Windows Update.
5. If problems persist, reset the update components by opening an elevated Command Prompt and running:
   • net stop wuauserv
   • net stop bits
   • net stop cryptsvc
   • ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
   • net start wuauserv
   • net start bits
   • net start cryptsvc

Software and malware

Background software can also cause instability.

1. Open Task Manager with Ctrl + Shift + Esc and review the Startup tab. Disable anything non-essential.
2. Perform a clean boot by pressing Windows + R, typing msconfig, and on the Services tab checking Hide all Microsoft services then clicking Disable all. Restart and test.
3. Run a full scan with Windows Security > Virus & threat protection > Scan options > Full scan.

Troubleshooting

Still restarting after all of the above?

Work through this final checklist before raising a ticket.

• Confirm the BIOS or UEFI firmware is up to date. Manufacturers release fixes for power and stability issues regularly.
• Reset Windows in place by going to Settings > System > Recovery > Reset this PC and choosing Keep my files.
• Back up your data and perform a clean installation of Windows from official media as a last resort.
• If the PC still restarts, the issue is almost certainly hardware. Contact the manufacturer or a qualified technician for component-level diagnosis.

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