Hi
Usually it is the CPU heating up too much, or a hardware problem. Are you having this issue?
Could also be a memory issue.
A good way to attempt to resolve it, is cleaning the inside of your computer tower. Especially taking a small brush to the bus modules of the memory. (Remove memory sticks carefully, then brush the modules out, finally put the memory back in). Also, cleaning the fans gently using a small brush should help as well.