|Well your PC is simply overheating. Do standard checks.|
Check to make sure your CPU fan is working properly, at full speed.
Make sure your motherboard and other hardware ain't covered in dust. Give it a good vacuum or use an air compressor to blast away the dust.
Make sure your PC is in an open, ventilated area.
See if it runs any better, if so install temperature software to monitor it.
If it's still going off and over heating rapidly, I assume it's an old PC and the processor has worn itself down.
If you need to buy a new processor, make sure you have a good heatsink + cooling fan before installing it. That will prevent it from overheating in the future.