Steps:
You can skip steps 1 & 2 if you have a cracked version of cod4 (not a legit key)
1. Go to your COD4 directory and find the "pb" folder.
2. Rename the folder to "asd" or anything except "pb", this will disable punkbuster.
3. Now open up COD4.
4. ALT+TAB to the desktop and open up EasyAccount.exe (run as administrator Vista/Win7)
4. Select your patch version (if you don't know which patch version you have, it's most likely 1.7, but you can open up "version.inf" in your COD4 directory and it tells you there)
5. Then select "Easy Upgrade"
6. Then exit out of EasyAccount and go into COD4.
7. Voila! You should be level 55 with all sorts of goodies unlocked.
Press the thanks button if I helped you.