Please help me... i have installt Call Of Duty MWF Before. but now when i try to install it again, et doesn't work. i have trye't to install it from the disc and from Steam. but when it is don, it kom's with af message, that show's "Preparing start of Call Of Duty MWF". I Have let it run on the screen on til it startet, but after about 15 hours, i gave up.

What is the problem, and have do i solve it?