Ok, now you have that, put it on the Desktop or somewhere easy accessible.
Now go to Start->Run->type Regedit ->Hit enter :: Like this:
Now, you go to HKEY_LOCAL_MACHINE->SOFTWARE->ACTIVISION->Call of Duty4 Like this:
Now, on the above image you can see a file called 'codkey'. Open that, and save the current code in notepad. Now enter this: DL2J8PY44Q22GE4888D2
Press ok, close regedit. Now find your COD4 Program File folder [Program Files-Activision-Call of Duty 4].
Now go to the folder name players, then another folder called profiles and click the folder of the account you wish to hack. back the files up and delete them. Now find your MPdata that you just downloaded, and put it in that folder.
Go on Cod and enjoy - 1 more thing.
Go onto Cod, Options, Multiplayer options and change your key back to your PROPER key what you should've saved on the desktop.
"Holding anger is a poison. It eats you from inside. We think that hating is a weapon that attacks the person who harmed us. But hatred is a curved blade. And the harms we do, we do to ourselves."-Mitch Albom