Well not crashing, but at random times during playing the game, singleplayer or multiplayer, my monitor switches off, goes black, as if it's gone to standby but theres nothing i can do to make it go back to the game, I just have to restart the computer.
It happens every time I play it can take five minutes or a few hours but it always happens.
Does anyone know what the problem is? Is there anything i can do? I'd appreciate some help, thanks.

i had this problem with some games on an older video card i had. It was by the company apollo, and i no longer buy anything from them. The best i could figgure was they used cheaper memory on the card and it would either overheat or get an error which caused the video card to lock up. for me, newer drivers seemed to make it worse, one thing that did help was i used a 3rd party program to underclock the memory speed. performance was less, but at least it was stable.

edit: btw the card i had was a radeon 8500, but apollo builds nvidia cards as well. i had it replaced once and it failed a second time. i'd recommend not buying anything from them. when i got mine they were bloody monster and devil monster cards (one for each company, ati and nvidia)