Black Screen on Windows 7

Hello,
Crossfire isn't working on my computer or laptop rather.
It turns on normally, but when it goes to the login place, it shows black screen (1/4 of my screen) When I move my mouse a little and click on something, it shows an error but it doesn't specify which kind of error it is. It just says "Crossfire Error".I'm not sure if this is windows 7's problem though. Please fix this.

Help please!

Thanks~