PC Repair

How to Stop Windows 11 from Randomly Restarting: Causes and Fixes

What You'll Achieve — and What You Need Before You Start

A Windows 11 PC that randomly restarts without warning is one of the most maddening tech problems you can face. Random restarts in Windows 11 are almost always caused by one of four things: a bad Windows Update, a failing or overloaded power supply, overheating hardware, or a corrupt driver. Follow the steps below and you'll go from "my computer reboots mid-sentence" to a stable machine that stays on when you tell it to. No reinstalls. No factory resets. No paying someone at a chain store €150 to do what you can fix in an afternoon.

Skill level required: Beginner to intermediate. If you can right-click a desktop and navigate a Settings menu, you can do this.
Time required: 30–90 minutes depending on which fix applies to you.
What you need: Your Windows 11 PC, an internet connection, and about 5 GB of free disk space for any driver downloads.

Step 1: Check the Windows Event Viewer for the Real Cause

Don't guess. Windows logs exactly what happened before every unexpected restart — most people just never look. Event Viewer is your black box flight recorder.

• Press Windows key + R, type eventvwr.msc, hit Enter.
• In the left panel, navigate to Windows Logs → System.
• Click Filter Current Log on the right side, then filter by Event Level: Critical and Error.
• Look for entries timed right before your last restart. Common culprits: Kernel-Power Event ID 41 (unexpected shutdown), BugCheck (Blue Screen of Death), or disk errors.

Kernel-Power 41 means Windows lost power unexpectedly — could be a dying PSU, a faulty power strip, or a hardware fault. BugCheck errors point to bad drivers or RAM. Write down whatever you find; it tells you which step below to jump to first.

Step 2: Disable Automatic Restart on System Failure

By default, Windows 11 reboots so fast after a crash that you never see the Blue Screen error code. That error code is exactly what you need. Turn off the automatic restart so you can actually read the message.

• Press Windows key + I to open Settings.
• Go to System → About → Advanced system settings.
• Under the Startup and Recovery section, click Settings.
• Uncheck "Automatically restart" under System failure.
• Click OK and restart your PC manually.

Next time it crashes, the blue screen will freeze on screen. Photograph the stop code (e.g. SYSTEM_SERVICE_EXCEPTION or MEMORY_MANAGEMENT) with your phone — that's your diagnosis in four words or less.

Step 3: Update or Roll Back Problematic Drivers

Drivers are the number one cause of random restarts in Windows 11, especially after a major Windows Update pushes an incompatible GPU or chipset driver. Here's how to deal with both scenarios.

If the restarts started after a Windows Update:

• Go to Settings → Windows Update → Update History → Uninstall Updates.
• Remove the most recent update and restart.
• If stability returns, pause updates for 7 days while Microsoft pushes a fix.

If the restarts are random and ongoing:

• Right-click the Start button, choose Device Manager.
• Look for any device with a yellow warning triangle — that's your suspect.
• Right-click the flagged device → Update driver → Search automatically.
• For graphics cards specifically, download the latest driver directly from NVIDIA, AMD, or Intel's website — not Windows Update. Chain-store "technicians" always miss this.

Step 4: Run a RAM Diagnostic

Faulty RAM is silent until it isn't. A single bad memory stick can cause random restarts, freezes, and BSODs for months before anyone thinks to test it. Windows has a built-in tool — use it.

• Press Windows key + R, type mdsched.exe, hit Enter.
• Choose "Restart now and check for problems".
• Windows will reboot into the memory test and run two full passes automatically.
• When it finishes, log back in and open Event Viewer → Windows Logs → System. Search for "MemoryDiagnostics-Results".

If errors are found, your RAM is the culprit. On a desktop, try removing one stick at a time and testing each individually. On a laptop, bring it to us — soldered RAM is not a DIY job.

Step 5: Check for Overheating

Costa Blanca summers are brutal. A laptop sitting on a sofa cushion in a 32°C room with a clogged fan is a machine that will restart itself to prevent permanent damage — that's called thermal shutdown, and it's actually Windows protecting your hardware. But it's still a problem you need to fix.

• Download HWMonitor (free, from CPUID.com) and run it while doing your normal tasks.
• Watch the CPU and GPU temperatures. Anything above 90°C under load is dangerous. Above 100°C and your machine is protecting itself by shutting down.
• If temps are high: clean the vents with compressed air, make sure the machine is on a hard flat surface, and check that the fan is actually spinning.
• If cleaning doesn't bring temps down, the thermal paste between the CPU and heatsink may need replacing — a €20 fix that extends a laptop's life by years.

Step 6: Check Your Power Supply and Power Settings

This one catches people off guard. A power supply unit (PSU) that's slowly dying will cause random restarts under load — the moment your GPU or CPU demands a power spike, the PSU can't deliver and the system drops dead. On laptops, a failing battery or a cheap third-party charger can do the same thing.

• If you're on a desktop: try plugging into a different wall socket, bypass any power strip or UPS, and listen for any clicking or buzzing from the PSU under load. A PSU tester costs about €15 at any electronics shop.
• If you're on a laptop: use only the original charger. Third-party chargers from Amazon often can't supply consistent wattage and trigger safety shutdowns.
• Check Windows power settings: go to Settings → System → Power & Sleep → Additional power settings and make sure you're on Balanced or High Performance — not a custom plan someone set up that throttles the CPU erratically.

If It Still Goes Wrong: Advanced Troubleshooting

You've worked through all six steps and the machine is still restarting. Here's what to try before calling it dead:

• Run SFC and DISM: Open Command Prompt as Administrator and run sfc /scannow, then DISM /Online /Cleanup-Image /RestoreHealth. Corrupt system files can cause instability that no driver update will fix.
• Check your SSD or HDD: Use CrystalDiskInfo (free) to check the health status of your drive. A drive showing "Caution" or "Bad" is failing and will cause random crashes — back up immediately and replace it.
• Test with a Live USB: Boot Ubuntu from a USB stick and use the PC for an hour. If it doesn't restart, the problem is Windows-specific (software). If it still restarts, the problem is hardware — and it's time to bring it in.
• Check for malware: Some aggressive malware and cryptominers push hardware so hard they trigger thermal or power shutdowns. Run a full scan with Malwarebytes Free.

You'll Know It Worked When…

Your machine runs for a full working day — video calls, browser tabs, documents, the lot — without a single unexpected restart. Open HWMonitor and confirm temperatures are sitting comfortably below 80°C under load. Event Viewer shows no new Kernel-Power 41 or BugCheck errors in the last 24 hours. That's a stable machine.

If you reach this point and the restarts have stopped, re-enable automatic restart in System Properties (Step 2 in reverse) so you don't get stuck on a BSOD screen if something new goes wrong down the line.

Still rebooting randomly after all of this? That's a hardware fault that needs physical diagnosis — a failing motherboard, degraded capacitors, or a component drawing unstable power. Bring it to Campoverde Repair. We'll tell you what's wrong within the hour, and we won't charge you €200 to format and reinstall Windows just to avoid actually fixing it.

Key Takeaways

• Kernel-Power Event ID 41 in Event Viewer is the most common log entry behind random Windows 11 restarts — always start there, not with guesswork.
• Disabling automatic restart lets you see the BSOD stop code, which cuts diagnosis time from hours to minutes.
• Drivers and Windows Updates are the leading software cause; overheating and failing PSUs are the leading hardware causes.
• Temperatures above 90°C under load mean your machine is shutting down to protect itself — cleaning vents or replacing thermal paste usually solves it.
• If the PC restarts even when booted from a Linux USB stick, the fault is hardware and no Windows fix will cure it.

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