Crossfire black screen????????

I can't even go to the login screen. I clicked on start game, then the gameguard appeared, then it went to black screen without going to the login screen. I've tried to uninstall it, fix the registry, and everything i can and it seems to not work. Anyone got the solution please post it as soon as possible. I'm using Window Vista service pack 1 now. I've just got this problem this morning and don't know why.