Why Does a Computer Restart by Itself?
Unexpected restarts are almost always the computer's way of protecting itself from a problem it cannot handle. The most common causes fall into a few categories.
- Overheating — the processor shuts down to prevent damage when it gets too hot
- A Windows update that requires a restart to finish installing
- A failing power supply that cannot deliver consistent power
- Faulty RAM (memory) causing the system to crash and restart
- A virus or malware that is triggering restarts
- A corrupted Windows system file
- A hardware driver that is conflicting with the operating system
Is It a Windows Update?
The most harmless cause of unexpected restarts is a pending Windows update. Windows sometimes schedules restarts automatically to finish installing updates, and these can happen at inconvenient times.
- 1Click the Start menu and open Settings
- 2Go to Windows Update
- 3Check if there are updates waiting to be installed or a restart pending
- 4If so, save your work, click Restart Now, and let the update complete
- 5After the update finishes, check if the random restarts stop
Tip: You can set Active Hours in Windows Update settings to tell Windows when you are typically using the computer. This prevents it from restarting during those hours.
Check for Overheating
Overheating is one of the most common causes of random restarts, especially on older computers or laptops used on soft surfaces like beds or couches.
- Feel the bottom of your laptop or the vents on your desktop — are they very hot?
- Listen for the fan running loudly or constantly
- Make sure vents are not blocked by dust, fabric, or objects
- For laptops, always use on a hard, flat surface — never on a bed or pillow
- If the computer restarts after heavy use (gaming, video calls, printing), overheating is likely
Tip: Dust buildup inside a computer is a leading cause of overheating. A professional cleaning once a year can significantly reduce heat-related restarts.
Steps to Try Before Calling for Help
Work through these steps in order. Many random restart problems are resolved by one of these fixes.
- 1Check for and install any pending Windows updates
- 2Run a full scan with Windows Defender to check for malware
- 3Make sure your computer is in a well-ventilated spot and vents are clear
- 4Uninstall any software or drivers you installed recently
- 5Check the Event Viewer (search for it in the Start menu) for error messages around the time of each restart
When to Call a Professional
Some restart problems require diagnostic tools and hardware testing that go beyond what most homeowners can do at home.
- The computer restarts every few minutes regardless of what you are doing
- Restarts are accompanied by a blue screen error
- The computer restarts immediately after booting up
- You have tried the steps above and the problem continues
- The computer is making unusual sounds (clicking, grinding, buzzing)
Warning: If your computer restarts repeatedly and you see a blue screen with a stop code like MEMORY_MANAGEMENT or KERNEL_SECURITY_CHECK_FAILURE, this may indicate failing hardware. Do not ignore it — call for help before the problem gets worse.