The most common causes of random restarts
A random restart usually means your computer encountered a problem it could not recover from, so it shut down and rebooted to try again. The restart happens without warning because Windows or your operating system is set to restart automatically when it detects a critical error — you do not get a choice or a countdown timer.
The most frequent culprits are overheating, a failing hard drive, outdated or corrupted drivers, malware, and power supply problems. Less often, a Windows update that went wrong or a hardware component coming loose inside the case will cause the same symptom. The restart can happen during normal use, during startup, or only when you run a specific program.
The key to fixing it is figuring out which of these is actually happening on your machine. A restart that happens only when you play games points to overheating or a graphics driver problem. A restart that happens randomly at any time, even when the computer is idle, points to malware, a power supply issue, or a failing drive.
Key Takeaways
- Random restarts are usually caused by overheating, driver problems, malware, failing hardware, or power supply issues — not a single universal cause.
- Check the Event Viewer log on Windows to see what error code the system recorded just before the restart, which narrows down the cause.
- Overheating is the easiest to test: shut down, open the case, and feel whether the CPU heatsink is hot and whether dust is blocking the fans.
- If restarts happen only during one activity (gaming, video editing, heavy downloads), the problem is usually driver-related or thermal, not a failing drive.
- Malware and power supply failures cause restarts at random times with no pattern, and both require professional diagnosis or replacement.
Check the Windows Event Viewer for error codes
Windows logs every restart and the error that triggered it. The Event Viewer is where you can read that log and see what your computer was actually complaining about. Open Event Viewer by pressing the Windows key, typing "Event Viewer", and pressing Enter.
Once it opens, click on "Windows Logs" on the left side, then click "System". You will see a long list of events. Look for entries marked "Critical" or "Error" that happened around the time your computer restarted. Click on one and read the details at the bottom — look for a code like "DRIVER_IRQL_NOT_LESS_OR_EQUAL" or "KERNEL_DATA_INPAGE_ERROR". These codes tell you what failed. Write down the code and search for it online to see what it means on your specific setup.
If you see no critical errors in the log, or if the log shows only "The system has rebooted without cleanly shutting down first", then Windows did not record what went wrong — this usually means a hardware failure, power loss, or malware that hid its tracks.
Test for overheating and dust buildup
Overheating is the easiest cause to check yourself. Shut down your computer completely, unplug the power cable, and wait five minutes. Then open the case — most modern cases have a side panel held by two or three thumbscrews or a latch.
Look at the large metal fins attached to the CPU (the processor, usually in the center of the motherboard under a large heatsink). Feel the heatsink with your hand — it should be warm, not hot enough to hurt. If it is very hot or if you see dust caked on the fins, that is your problem. Use a can of compressed air to blow dust out of the heatsink and the case fans. Blow from inside the case outward, not the other way around.
Restart the computer and run it for 30 minutes doing something demanding, like playing a game or running a video export. If it does not restart, overheating was the cause. If it still restarts, move on to the next step.
Update or reinstall your drivers
A driver is software that lets Windows talk to a piece of hardware — your graphics card, network adapter, motherboard chipset, and so on. A corrupted or outdated driver can cause the system to crash and restart.
Start with your graphics driver, since that is the most common culprit. If you have an NVIDIA card, go to nvidia.com/read/driverDetails.html. If you have AMD, go to amd.com/en/support. If you have Intel integrated graphics, go to intel.com/content/www/us/en/support/detect.html. read the latest driver for your exact card model and Windows version, then run the installer and restart.
If the restarts continue, update your chipset driver next. Go to your motherboard manufacturer's support page (ASUS, MSI, Gigabyte, or whoever made your board), find your exact model, and read the chipset driver. Install it and restart again.
If you cannot find your motherboard model, open Device Manager by pressing Windows key + X and clicking "Device Manager". Look under "System devices" for something like "Intel 100 Series Chipset" or "AMD X570". Search for that exact name online along with your Windows version to find the right driver.
Scan for malware with Windows Defender and Malwarebytes
Malware can cause random restarts by consuming resources, corrupting system files, or triggering a crash on purpose. Windows Defender is built into Windows 10 and 11, but it is worth running a full scan to be sure.
Open Windows Security by pressing the Windows key and typing "Windows Security". Click "Virus and threat protection", then click "Scan options". Select "Full scan" and click "Scan now". This will take 30 minutes to an hour. Let it finish and restart if it finds anything.
After that, read Malwarebytes from malwarebytes.com. The free version is enough for a one-time scan. Install it, open it, and click "Scan". Let it run to completion. If it finds anything, click "Quarantine" and restart.
If the restarts stop after cleaning malware, you are done. If they continue, the problem is hardware-related.
Test your hard drive and power supply
A failing hard drive or solid-state drive can cause random restarts because the system cannot read or write data reliably. Windows has a built-in tool to check this. Open Command Prompt as administrator by pressing Windows key + X and clicking "Terminal (Admin)". Type this command and press Enter:
chkdsk C: /F /R
Windows will ask if you want to schedule the check for the next restart. Type "Y" and press Enter. Restart your computer. The check will run before Windows loads — this takes 10 to 30 minutes depending on your drive size. Let it finish without interrupting.
If the check finds and fixes errors, restart again and see if the random restarts have stopped. If the check finds many errors or cannot fix them, your drive is failing and needs replacement.
A failing power supply is harder to test at home. If your computer restarts only when you are running demanding programs (games, video editing, heavy downloads), and if the Event Viewer shows no errors, the power supply may not be delivering enough power under load. This requires a replacement — a power supply is not worth repairing. Take the computer to a repair shop and ask them to test the power supply under load.
When to take it to a repair shop
If you have worked through the steps above and the restarts continue, the problem is likely a hardware failure that requires professional diagnosis. A failing motherboard, a bad RAM stick, or a power supply issue cannot be fixed by the user and need a technician with test equipment.
Before you go, write down what you have already tried — overheating check, driver updates, malware scans, hard drive check. Tell the technician what you found in the Event Viewer, if anything. This saves them time and gets you a faster answer.
If your computer is still under warranty, contact the manufacturer first. If it is out of warranty, a local repair shop will usually charge between $50 and $150 for diagnosis, then quote you a price for the repair or replacement part.
Frequently Asked Questions
Can a Windows update cause random restarts?
Yes. A failed or incomplete update can corrupt system files and cause restarts. If the restarts started right after an update, restart in Safe Mode (hold Shift while clicking Restart from the power menu), then go to Settings > Update & Security > Recovery and click "Reset this PC". Choose "Keep my files" to reinstall Windows without losing your data.
Why does my computer restart only when I play games?
Gaming puts heavy load on your graphics card and CPU, so it exposes overheating, driver problems, or power supply issues that do not show up during normal use. Update your graphics driver first, then check for dust and overheating. If that does not work, the power supply may not be delivering enough power.
Is a random restart dangerous for my files?
A restart can corrupt files that were open and unsaved at the moment it happened. It is not dangerous to the hard drive itself. Save your work frequently and consider enabling autosave in programs like Word and Google Docs so you do not lose data between restarts.
What if the restart happens during startup, before Windows fully loads?
This usually means a hardware problem — bad RAM, a failing drive, or a loose component. Restart in Safe Mode by holding Shift while clicking Restart, then go to Settings > System > Recovery > Advanced startup options > Restart now. Choose "Troubleshoot" > "Advanced options" > "Startup Repair" and let it run. If that does not work, the hardware needs professional testing.
Can I disable automatic restart so I can see the error message?
Yes, but it is not recommended because it can leave your system in a bad state. If you want to try it: right-click "This PC" or "My Computer", click Properties, click "Advanced system settings", click the "Advanced" tab, and under "Startup and Recovery" uncheck "Automatically restart". Now when an error happens, you will see a blue screen with a code instead of an automatic restart. Write down the code and search for it.