Q:
A: If it's just restarting by itself a good diagnosis would be that your motherboard is shot or your power supply is broken. Don't know what kind of computer you have or how old it is. I have had both of my motherboard and power supply go and a few computers in the past. PS are not expensive and can be easily installed. motherboards can be much more expensive and much more technical. Or just buy a new PC... if you have the money.