idude and Tigerlors:
Hi, my name's Cody, and I'm working with the Windows Gaming Outreach Team. After seeing several online threads where users were experiencing similar problems to yours, it seems most likely that your issues are being caused by issues with your graphics cards and/or DirectX. Here's a great link that has several options for you to fix your issues:
SLI Zone Forums > Call of Duty4: won't even start I hope you find something useful there! Let me know if I can help in any other way.
Thanks,
Cody
Windows Gaming Outreach Team