How to understand why the PC turns off?

Question

Computers

• Intel Xeon CPU E3-1230 V2 3.30Ghz
  
• RAM: 8GB
  
• Radeon HD 4600 series(Temporary plug)
  
• SSD Kingston SA400S37240G
  

Recently, it has been abruptly cut down on its own (maybe in the game and just in the browser), how to see the reason for the shutdown?

Answer 1

Overheating, check using, for example, OpenHardwareMonitor, you can watch the temperature in the tray or write logs. With a probability of 99% - the processor.
The solution is to replace the thermal paste on the processor or even its cooling system.