Call of Duty 5 issues

Does it play if you don't choose a Level?
If Running Windows try launching the game, hit Ctrl+Alt+Delete go to Processes and try to assign a higher priority, like Above Normal or than try, High. Than go back to the game. I hope that works!
If that don't do it not sure but just a thought if that picture is your machine you my need a little more umpf to keep it running.

I did more research on it, for some reason windows 7 didn't write my product key to the registry, and when I added the entries, the game didn't seem to look for them. But I'm running fine in vista!!! Thanks,