It only crashes, doesn't reboot. And yes, my friend is rich :° I want to be rich aswell >.<
I think the older driver solution solved it, he had the 71.xx and all games were crashing after 30min so he had to use the old ctrl+alt+del ¬_¬
Now he installed older drivers and everything is back to normal, thanks everybody.
Oh, and yeah, nVidia has a 512MB card that is NOT 2 cards of 256MB connected by SLI, and I think this one also supports SLI, just imagine 1024MB of graphic card ^_^