Have you tried remove or disable one of your video card? I mean not only disable crossfire, but disable one video card in control panel completely.
I'm not sure if it will work, though.
Ok Disabling the second graphics card got the graphics working but, the game now crashes during the intro movies or at the main menu. Tested several compatibilities modes just in-case, no luck.
Is your screen resolution larger than 1600x1200? You have to reduce resolution if it's too large.