After 2 hours of gameplay I started to have crashes like in the tittle!

My computer specs are sa follows:

Nvidia GeForce GTX 760 2 gb ram,

AMD Phenom 2 x4 965 Black Edition 3x3,4 mhz,

8 gb ram (Kingston)

Windows 7 Home Premium 64 bit (without ANY updates and service packs) Don't ask please!

Game is running like a charm on ultra settings besides all the driver crashes!!!

PLEASE HELP ME !!!