Aah since it also crashes with skirmish, we can verify that it isn't only related to multiplayer. This simplifies things.
I had this problem myself, shutting down replays worked for me. It also improved my performance and stopped the horrible freezes. Follow this guide when disabling the replays: http://steamcommunity.com/sharedfiles/filedetails/?id=156776308
If this doesn't work, reinstall Coh2 after you reinstalled your current drivers.
ok if tried it but it still crashed after some time ingame ...