Computer shuts down after some minutes

[Googolplex]

I know that Amnesia or other games doesn't cause overheating problems! The problem is in my hardware. But it's different from game to game. I don't want that I can't play AAMFP when it's out. But when it's using the same engine threading or what ever like TDD, then it will working fine. But when the devs add some Dear Esther features to engine, it probably could kill my PC.

As I said, the fan and cooler are mounted correctly. Perhaps the cooler is to weak for my CPU, but I never had the problems all the years before. And I think, even the intel standard cooler should be enough when CPU is fully utilized.