Why Does My Computer Keep Restarting by Itself? (September 2026) Guide

There is nothing more frustrating than being in the middle of a project, a game, or an important video call when your computer decides to restart without warning. If your computer keeps restarting by itself, you are dealing with a problem that affects thousands of PC users every single day. The good news is that most random restart causes are diagnosable and fixable without a trip to the repair shop.

Our team has spent years troubleshooting computers in homes, offices, and gaming setups. In that time, we have seen just about every restart scenario imaginable. From PCs that reboot every ten minutes to systems that crash only during intense gaming sessions, the underlying causes almost always fall into a handful of categories. Once you understand what triggers an unexpected reboot, fixing the problem becomes a straightforward process of elimination.

This guide walks you through every major reason why a computer keeps restarting by itself, from overheating processors to failing power supplies and corrupted drivers. You will find specific diagnostic steps, real Windows commands you can run right now, and clear solutions for each cause. We also cover gaming-specific restarts, pre-BIOS boot loops, and no-display scenarios that stump most users.

By the end of this article, you will have a complete troubleshooting roadmap. Whether you are a casual user or someone who pushes their hardware to the limit, these steps will help you stop random restarts and protect your system from future damage. Let us start with the most common culprit behind unexpected reboots.

Why Does My Computer Keep Restarting by Itself? The Top Causes

A computer that keeps restarting by itself is almost always responding to one of six triggers: overheating, power instability, hardware failure, driver conflicts, Windows Update behavior, or malware infection. When your system detects a condition that could damage components or destabilize the operating system, it triggers an automatic reboot as a self-protection measure. The challenge is figuring out which of these triggers applies to your situation.

The timing of the restart tells you a lot about the cause. Restarts that happen during heavy use like gaming or video editing usually point to overheating or power supply problems. Restarts that occur at random intervals during normal tasks often indicate driver conflicts or malware. Restarts that happen in a continuous loop before Windows even loads suggest a hardware or BIOS issue. We will cover each cause in detail below.

Overheating: The Number One Cause of Random Restarts

Overheating is the single most common reason a computer keeps restarting by itself. Modern processors and graphics cards have built-in thermal protection that shuts down or restarts the system when temperatures reach dangerous levels. For most CPUs, that critical threshold sits around 90 to 105 degrees Celsius, while GPUs typically trigger thermal shutdown between 90 and 110 degrees Celsius.

Dust buildup is usually the root cause. Over months of use, dust collects on fans, heatsinks, and air intake vents, choking the airflow your components need to stay cool. A system that ran perfectly fine when clean can start restarting after just six months of dust accumulation. Thermal paste between your CPU and its cooler can also dry out over time, losing its ability to transfer heat efficiently.

To check your temperatures, download a free monitoring tool like HWMonitor or Core Temp. Run it in the background while you use your computer normally. If your CPU regularly hits 85 degrees Celsius or higher during everyday tasks, or your GPU exceeds 80 degrees during gaming, you have an overheating problem. The fix involves cleaning dust from your fans and heatsinks, reapplying thermal paste, and ensuring your case has adequate airflow with properly configured intake and exhaust fans.

Power Supply Problems and Electrical Issues

Your power supply unit (PSU) is the heart of your system, and when it starts failing, random restarts are often the first symptom. A PSU that can no longer deliver consistent voltage to your components will cause the system to reboot under load. This happens because aging capacitors inside the power supply degrade over time, reducing their ability to filter voltage spikes and dips.

Sometimes the problem is not the PSU itself but an overloaded circuit. If your computer, monitor, speakers, and other devices all share a single power strip, voltage drops during peak demand can trigger restarts. Power surges from appliances cycling on and off elsewhere in your home can have the same effect. Always connect your computer to a surge protector rated for at least 1000 joules, and avoid daisy-chaining power strips.

If you suspect your PSU is failing, look for warning signs like restarts that happen specifically under heavy load, a burning smell near the power supply, or a PSU fan that has stopped spinning. Desktop users can test this by swapping in a known-good power supply. Laptop users should check whether the restarts only happen on battery power, which would indicate a failing battery rather than the charger.

Faulty or Failing RAM

Bad RAM is a sneaky cause of random restarts because it does not always produce a blue screen error first. When a memory module develops errors, your system may silently crash and reboot without any visible warning. This is especially common in systems that have been running for years or in computers that experienced a power surge.

The fastest way to test your RAM is with Windows Memory Diagnostic, which is built into Windows 10 and Windows 11. Press the Windows key, type “Windows Memory Diagnostic,” and select “Restart now and check for problems.” Your computer will reboot and run a memory test that takes about fifteen minutes. If it finds errors, you likely have a failing stick of RAM.

For more thorough testing, download MemTest86 and run it from a USB drive. This tool performs deep memory testing that catches errors the built-in tool misses. If you find errors, remove your RAM sticks one at a time and test each individually to identify the bad module. Replacing a faulty RAM stick is inexpensive and usually eliminates the restarts immediately.

Driver Conflicts and Corruption

Drivers are the software bridge between Windows and your hardware, and when they conflict or become corrupted, the result is often an unexpected restart. Graphics drivers are the most common offenders, especially after an update that did not install cleanly. Audio drivers, network adapter drivers, and chipset drivers can also cause problems.

Restarts that begin immediately after a driver update are a dead giveaway. You can roll back a problematic driver through Device Manager. Right-click the Start button, select Device Manager, find the device in question, right-click it, and choose Properties. Under the Driver tab, click “Roll Back Driver” if the option is available.

For a cleaner fix, uninstall the driver completely and download the latest version directly from the manufacturer. For graphics cards, get drivers from NVIDIA, AMD, or Intel rather than through Windows Update. Use Display Driver Uninstaller (DDU) to completely remove old GPU drivers before installing fresh ones, as leftover files from previous driver versions are a frequent source of conflicts.

Windows Updates and the Automatic Restart Feature

Sometimes the answer to why your computer keeps restarting by itself is simply Windows Update. When Windows downloads updates in the background, it may restart your computer automatically to install them, often at the worst possible time. This is not a malfunction but a setting you can control.

To manage this, go to Settings, then Update and Security, then Windows Update. Click “Change active hours” and set the times you actively use your computer. Windows will avoid restarting during those hours. You can also pause updates for up to five weeks if you need more time.

The Fast Startup feature in Windows 10 and Windows 11 can also cause restart issues. Fast Startup saves system state information to speed up boot times, but it can interfere with driver initialization and cause crashes on wake. To disable it, press Windows plus R, type “powercfg.cpl,” click “Choose what the power buttons do,” then “Change settings that are currently unavailable,” and uncheck “Turn on fast startup.” Many users report this single change eliminates their random restarts entirely.

Another useful setting is disabling automatic restart on system failure. Press Windows plus R, type “sysdm.cpl,” go to the Advanced tab, and under Startup and Recovery, click Settings. Uncheck “Automatically restart.” This will not stop the underlying crash, but it will let you see any blue screen error code that appears, which makes diagnosis much easier.

Malware and Virus Infections

Malware is a less common but real cause of random restarts. Some viruses are designed to reboot your system as part of their infection process, while others corrupt system files so thoroughly that Windows crashes and restarts to recover. If your computer started restarting after you downloaded a suspicious file or visited an unfamiliar website, malware is a strong suspect.

Run a full system scan with Windows Security, which comes built into Windows 10 and Windows 11. Open Windows Security, click “Virus and threat protection,” then “Scan options,” and select “Full scan.” This can take over an hour depending on your drive size. For stubborn infections, download Malwarebytes and run its free scanner as a second opinion.

If malware is found and removed but restarts continue, the infection may have damaged system files. Open Command Prompt as administrator and run “sfc /scannow” to check for and repair corrupted system files. Follow that with “DISM.exe /Online /Cleanup-image /Restorehealth” to repair the Windows image itself. These two commands fix a surprising number of deep system issues.

Failing Motherboard or Other Hardware

When you have ruled out every other cause, a failing motherboard becomes the prime suspect. Motherboard failures are notoriously difficult to diagnose because the symptoms mimic other problems. A failing voltage regulator module (VRM) on the motherboard can cause the same random restarts as a failing power supply. Swollen or leaking capacitors on the board can cause instability under load.

Look for physical signs of motherboard failure: bulging or leaking capacitors near the CPU socket, scorch marks on the board, or a burning plastic smell. Check that all power connectors are firmly seated, especially the 24-pin main connector and the 4-pin or 8-pin CPU power connector. A loose CPU power cable can cause restarts under load even when everything else looks fine.

If your system is several years old and you have exhausted all other causes, a dying motherboard is a reasonable conclusion. Unfortunately, replacing a motherboard is one of the most expensive repairs and often signals that it is time to consider a system upgrade rather than a fix.

When Your PC Keeps Restarting During Gaming

Gaming pushes your hardware harder than almost any other activity, which is why gaming-specific restarts deserve their own section. If your computer runs perfectly during normal use but restarts the moment you launch a demanding game, the cause is almost always one of three things: overheating under load, an insufficient power supply, or GPU driver problems.

We have seen reports from users whose GPU temperatures hit 80 to 90 degrees Celsius during gameplay in titles like Call of Duty and Cyberpunk. At those temperatures, the GPU thermal protection triggers and the system restarts to prevent damage. The solution is better cooling: clean your GPU fans, improve case airflow, lower in-game graphics settings to reduce heat output, or consider an aftermarket GPU cooler.

Power supply capacity is the other major factor. Gaming can double or triple your system’s power consumption compared to idle. A PSU that handles everyday tasks fine may fail under gaming load if it does not have enough wattage headroom. Use an online power supply calculator to estimate your system’s peak power draw, then make sure your PSU provides at least 20 percent more wattage than that number. If you are running a high-end GPU on a budget 500-watt power supply, upgrading to a quality 750-watt or 850-watt unit is likely the fix.

Overclocking is another frequent cause of gaming restarts. If you have overclocked your CPU or GPU for extra performance, the increased voltage and heat can destabilize your system. Try reverting to stock speeds and voltages. If the restarts stop, your overclock was the culprit. Re-tune your overclock gradually with thorough stability testing using tools like Prime95 for CPU and FurMark for GPU.

PC Keeps Restarting Before BIOS or With No Display

A computer that restarts before the BIOS screen even appears is in a different category entirely. This type of restart loop happens before Windows loads, which means the problem is below the operating system level. You are looking at a hardware issue, a BIOS configuration problem, or a power delivery failure.

The most common cause of pre-BIOS restart loops is a loose hardware connection. Over time, vibration, temperature changes, and physical movement can cause components to shift slightly in their sockets. Reseat your RAM by removing each stick and snapping it firmly back into place until the retention clips click. Do the same with your graphics card and all power cables. This simple step fixes a surprising percentage of boot loop problems.

If reseating components does not help, reset your BIOS to default settings. You can do this by clearing the CMOS, which involves removing the coin-sized battery on your motherboard for about five minutes, then reinserting it. This resets all BIOS settings to factory defaults, which eliminates problems caused by incorrect memory timings, overclocking profiles, or boot order changes. On some motherboards, you can also clear CMOS by shorting two pins labeled “Clear CMOS” or “JBAT1.”

A no-display restart scenario adds another layer of confusion. Your computer appears to restart but nothing shows on your monitor, making it seem like the system is completely dead. In most cases, the problem is a monitor connection issue rather than a system failure. Check that your monitor cable is connected to your graphics card, not the motherboard video port. Test with a different cable if possible. If you have integrated graphics, remove your discrete GPU and connect the monitor directly to the motherboard to see if the system boots normally.

If none of these steps resolve a pre-BIOS or no-display restart loop, you are likely dealing with a failed component. The most common culprits are a dead power supply, a failed motherboard, or a corrupted BIOS chip. At this point, professional diagnosis is the most practical next step.

Step-by-Step Troubleshooting Guide

When your computer keeps restarting by itself, working through a systematic diagnostic process saves time and prevents you from replacing parts that do not need replacing. Follow these steps in order, from simplest to most advanced. Stop when you find the fix.

Step 1: Disable automatic restart on system failure. Before anything else, stop Windows from hiding the real error. Press Windows plus R, type “sysdm.cpl,” go to the Advanced tab, and under Startup and Recovery, click Settings. Uncheck “Automatically restart.” Now, if your system crashes, you will see a blue screen with an error code instead of a silent reboot. Write down any error codes you see and search them online for specific solutions.

Step 2: Check the Event Viewer. Windows logs every crash and unexpected event. Right-click the Start button and select Event Viewer. Navigate to Windows Logs, then System. Look for events labeled “Critical” with the source “Kernel-Power” (Event ID 41), which indicates an unexpected shutdown. Check the events immediately before the crash for clues about what caused it, such as driver errors or hardware warnings.

Step 3: Disable Fast Startup. Fast Startup is a known cause of random restarts. Press Windows plus R, type “powercfg.cpl,” click “Choose what the power buttons do,” click “Change settings that are currently unavailable,” and uncheck “Turn on fast startup.” Restart your computer and see if the random restarts stop.

Step 4: Update or roll back your drivers. Open Device Manager and check for any devices with yellow warning triangles. Update your graphics drivers from the manufacturer website (NVIDIA, AMD, or Intel), not through Windows Update. If restarts started after a recent driver update, roll back to the previous version. For graphics drivers specifically, use Display Driver Uninstaller to completely remove old drivers before installing new ones.

Step 5: Run Windows Memory Diagnostic. Press Windows, type “Windows Memory Diagnostic,” and select “Restart now and check for problems.” Your computer will run a memory test and report any errors. If errors are found, test each RAM stick individually to identify the bad module and replace it.

Step 6: Scan for malware. Open Windows Security, go to “Virus and threat protection,” select “Scan options,” and run a “Full scan.” Follow up with Malwarebytes if you want a second opinion. Remove any threats found and restart your computer.

Step 7: Repair system files. Open Command Prompt as administrator. First run “sfc /scannow” to find and repair corrupted system files. Then run “DISM.exe /Online /Cleanup-image /Restorehealth” to repair the Windows system image. These commands can take twenty to thirty minutes each but fix a wide range of deep system corruption.

Step 8: Boot into Safe Mode. Hold Shift while clicking Restart from the Start menu, then choose Troubleshoot, Advanced options, Startup Settings, and press 4 or F4 for Safe Mode. If your computer runs fine in Safe Mode without restarts, the problem is software-related, likely a driver or startup program. Use a clean boot to isolate the culprit.

Step 9: Perform a clean boot. Press Windows plus R, type “msconfig,” go to the Services tab, check “Hide all Microsoft services,” then click “Disable all.” Go to the Startup tab and open Task Manager to disable all startup items. Restart your computer. If the restarts stop, re-enable items one at a time until the restarts return, which identifies the problematic software.

Step 10: Check temperatures and power. Install HWMonitor and watch your CPU and GPU temperatures during normal use and under load. If temperatures are dangerously high, clean your cooling system. If you suspect a power supply issue and you have a desktop, test with a different PSU if one is available.

Diagnostic Tools and Professional Repair Costs

Having the right tools makes diagnosing random restarts dramatically easier. The diagnostic tools recommended by the PC building and tech support communities are free or low-cost, and they cover every major subsystem in your computer. Here is what we recommend based on years of real-world troubleshooting experience.

For temperature monitoring: HWMonitor is the community favorite. It shows real-time temperatures for your CPU, GPU, motherboard, and storage drives in a single window. Core Temp and HWiNFO64 are solid alternatives. Run any of these in the background while you use your computer to catch temperature spikes that coincide with restarts.

For memory testing: MemTest86 is the gold standard. It runs from a USB drive and performs exhaustive testing that catches intermittent memory errors the Windows diagnostic tool misses. A full pass takes one to three hours depending on your RAM size. If MemTest86 reports even a single error, you have faulty RAM.

For CPU and GPU stress testing: Prime95 stresses your CPU to its limits, while FurMark pushes your GPU to maximum load and temperature. Run these for fifteen to thirty minutes. If your system restarts during a stress test, you have confirmed a hardware instability issue, and the temperature readings during the test tell you whether it is thermal or power related.

For system file repair: The built-in “sfc /scannow” and DISM commands are your first line of defense against corrupted system files. For deeper issues, CHKDSK (run as “chkdsk /f /r” in an elevated Command Prompt) scans your drive for physical errors and attempts recovery of readable data.

If none of these tools and steps solve your problem, professional repair becomes the practical option. Knowing what to expect cost-wise helps you decide whether a repair makes financial sense. Typical diagnostic fees at computer repair shops range from $50 to $100, which is often waived if you proceed with the repair through the same shop. RAM replacement typically costs $40 to $120 depending on capacity and speed. Power supply replacement runs $60 to $150 for the part plus $50 to $100 for labor. Motherboard replacement is the most expensive repair at $150 to $400 for the board itself, often making replacement of the entire system more cost-effective for older computers.

Before paying for professional diagnosis, try the troubleshooting steps in this guide. We estimate that 70 to 80 percent of random restart problems are resolved by the steps above without any professional intervention. Save your money for cases where a hardware swap is genuinely needed.

How to Prevent Random Restarts

Preventing random restarts is far easier than diagnosing them after the fact. A few maintenance habits go a long way toward keeping your system stable. Clean dust from your computer’s fans and vents every three to six months using compressed air. A can of compressed air costs about $8 and prevents the overheating that causes most restarts.

Keep your operating system and drivers updated, but avoid installing updates the moment they release. Waiting a few days lets other users discover problems before you do. Always download GPU drivers from the manufacturer rather than relying on Windows Update, which sometimes serves older or incompatible versions.

Use a quality surge protector rated for at least 1000 joules, and replace it every two to three years since surge protection components degrade over time. For areas with frequent power fluctuations, consider an uninterruptible power supply (UPS) that provides battery backup during outages and conditions the power going to your computer.

Run a malware scan monthly and keep Windows Security or your preferred antivirus active at all times. Avoid installing software from unverified sources, as malware is a common cause of system instability. Finally, monitor your system temperatures periodically with HWMonitor. Catching a rising temperature trend early lets you address cooling problems before they cause restarts or permanent hardware damage.

FAQ

Conclusion

Figuring out why does my computer keep restarting by itself comes down to a process of elimination, but that process is highly effective when you follow it systematically. The vast majority of random restarts trace back to overheating, power supply issues, driver conflicts, faulty RAM, or Windows settings like Fast Startup and automatic restart. By working through the troubleshooting steps in this guide, you can identify the specific cause and apply the right fix without guessing.

Remember that the timing of your restarts is your biggest diagnostic clue. Restarts during gaming point toward thermal and power issues. Random restarts during normal use suggest drivers, malware, or RAM problems. Restart loops before the BIOS screen indicate hardware or BIOS configuration failures. Match your symptoms to the relevant sections in this guide for the fastest path to a solution.

We recommend starting with the simplest fixes first. Disable Fast Startup, disable automatic restart on system failure, and check Event Viewer for error codes. These three steps take less than ten minutes and solve a surprising number of cases. From there, move through the diagnostic tools and testing procedures we covered, and do not skip the memory test. Faulty RAM is easy to miss but easy to fix.

If you have tried every step in this guide and your computer keeps restarting by itself, it is time to consider professional diagnosis or hardware replacement. A failing power supply or motherboard will not fix itself, and continuing to run failing hardware risks permanent data loss. But with the knowledge you now have, you can approach that conversation with a repair shop knowing exactly what has already been tested and what the likely culprit is. That knowledge alone can save you money and ensure you only pay for repairs you actually need.