for the third time now my computer has restarted on its own while playing counter strike source. this has never happend to me before untill now. when I restart it says the system recovered from a critical error and asks if i want to send an error report. I was told this is from overheating? I put my hand behind the computer and I can feel the fan blowing so its not that the fans dead. also.. it doesn't feel very hot back there. is there something else that could be causing this? is it overheating? how do I fix it?