I have the same problem too with Crysis and Crysis Warhead. Game works perfect untill my monitor turns off and goes to stand by mode but I can't wake him up anymore so I have to restart the computer. I tried almost everything: I changed refresh rate of my monitor and it helpet a little (previously monitor turned off directly after the game loaded, with refresh rate changed it works from 30 seconds to 5 minutes, but no more than that). I reinstalled drivers for several times but nothing help, I deleted the folder in my documents and it didn't help.

I have ATI HD 4850 and all other new games work perfect.

try turnign the fan up sounds like the card is over heating and shutting offf

markec123