Computer shuts down after some minutes

[Googolplex]

Hello.
My problem is, that my computer is going off when playing some games like Dear Esther, The Witcher 2, NFS Shift 2, Dirt, Among the Sleep etc.

That doesn't has anything todo with the graphics. Dirt for example is from 2006 and it's shutting down my computer even when I play on low resolution and details. My PC is powerfull enough, there is no stuttering on high graphics, but the PC just going off as I would cut the power cable.
There is no error message! After one minute of waiting I can turn my PC on again. I already cleaned my PC from dust, removed all components!

Amnesia TDD doesn't cause this problem.
So my question is, how much thechineseroom modified the engine. Are there new shaders, or multithread tasks? Did they add some programming features of Dear Esther?


I don't want that my PC turns off when playing AMFP.

Intel Core 2 Quad Q9550 4x 2,83 GHz
4 GB DDR2-RAM800 Dual Channel
nVIDIA GeForce GTX 560 Ti
550W BeQuiet! power supply


In short: Is the engine more like TDD or like Dear Eshter? What is different to TDD, what are the engine updates?

I don't want to buy a new PC, because my current one is powerfull enough. What could be the problem?