Why does my PC keep restarting randomly?

 Why does my PC keep restarting randomly? 

1. Overheating – A computer automatically restarts when a certain temperature (depends on the BIOS settings but usually in the 70-100 °C range) is reached to prevent damage to components, so it’s imperative that you check for overheating. 
2. Power failure – If the computer (desktop) doesn’t have a stable power supply, it will keep restarting randomly. 
3. Issues with the hardware – If the RAM or CPU fails, the computer will restart without any indication. 
4. A problematic app, process, or driver causing the restart – Any of the three can trigger a restart, so you will have to check for each. 
5. Bug in the installed version of the OS – Many users reported the problem after updating the OS, which arises due to a bug in the last installed version. You could either wait for a new version or revert to the previous stable release.