Me too, well 98%i must be the few that Windows 7 is working 100%...
Hello
I had the same problem with COD4, first I went to PunkBuster Online Countermeasures select COD4 -> Software Updates: Download
Follow the instructions and try to play
I do that... and servers still kick me
After that fail jaja, i downloaded PBSETUP and this little program update my PB to a higher version.
And works for me, in this moment my COD4 is minimized and no kicks for 30 minutes and counting xD