GTX 570 stops working CoD MW3

I experience issues when playing CoD Modern Warfare 3 for some time. My settings are 1920x1080 4x AA everything on Extra.

My system: Gygabyte Geforce GTX 570 OC

i5 2500K

Asus P8Z68 V PRO

Corsair Vengeance CL9 1600Mhz 2x4GB

Corsair HX 750W

After playing sometime the screen turns gray and I have to reboot. I ran Fur Mark for an hour and monitored the GPU temps. It reached 75 degrees C at most which is nothing to be worried about. I have the latest Nvidia drivers installed. I haven't experienced issues when playing other games.

What should I do?

Thanks for help.