Call of Duty 4 is an old game. It actually supports only Windows XP the best. I have Windows 7, it works but it has small problems like yours. It is not problem of the Windows, the real reason is that your version is old (1,7 is the newest) and your Windows are new. The only thing you need is some settings and commands (the command will be written in CoD4 command line, to fix fps, e.t.c.). If you want any halp, ask me to write commands for you!