Symptoms
- Computer powers off instantly with no blue screen or warning
- Shutdowns happen more during gaming or other demanding tasks
- PC restarts fine afterward like nothing happened
- Problem happens more in a warm room or after long sessions
Likely causes
- CommonCPU or GPU overheating and triggering a protective shutdownModern hardware shuts down instantly to prevent heat damage.
- CommonPower supply failing or undersized for the components under loadA PSU nearing failure often shows up first as random shutdowns under load.
- PossibleLoose power cables, especially the CPU or 24-pin motherboard connectorA marginal connection can drop out under vibration or heat.
- PossibleFaulty wall outlet or power strip causing brief power lossRule this out by testing a different outlet.
- Less commonWindows set to shut down instead of restart on certain critical errorsThis can make a crash look like a simple shutdown.
What to do
- Check CPU and GPU temperatures with monitoring software during normal and heavy use to see if shutdowns coincide with high heat.
- Clean dust from all fans, heatsinks, and the case interior.
- Reseat the 24-pin and CPU power connectors to rule out a loose connection.
- Try a different wall outlet or power strip, especially if shutdowns happen inconsistently.
- If the PSU is old or was on the smaller side for the system's power needs, consider testing with a known-good, adequately rated PSU.
- Check the Windows Event Viewer for any critical errors logged right at the time of the shutdown for more clues.
Tools and parts
- Temperature monitoring software
- Compressed air
When to call a pro
If shutdowns continue after ruling out heat, cables, and the outlet, have the power supply tested or replaced by a professional, since a failing PSU can be intermittent and hard to diagnose at home.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.