QUOTE(Old Man Mike @ 11/08/07 7:53am)

(I posted this in another thread and thought it should be restated in a new thread)
There is a way to play a modded server without losing rank. (I lost my rank in the process of learning how to do this so try not to kill the Old Guy while he rebuilds it back up)
1) Go to your player's profile folder containing the config_mp.cfg
2) Create a subfolder called "backup"
3) Copy the config_mp.cfg and mpdata files to that backup folder
4) You can now play on a modded server. After you are done, copy the two files in the backup folder back to the player's profile folder.
5) You can now return to a ranked server with no loss of rank.
Old Man Private Ranked Mike
For tricks like this I usually use a batch file (or .bat file). In a .bat file you can write in the commands in a text file to copy or move files from one location to another. Then you save the file to your desktop with a BAT extension, and you can make the moves by just double-clicking on the icon for the file. IN FACT, you could make two batch files if you wish, one for modded server, and one for un-modded, that copy the proper files then launch the game directly from the .bat file.
I don't have the game so I won't bother writing an example, but MIke or someone may have the gist of what I'm saying and could write up an example batch file for COD4.
Though one would hope they'll patch this soon. Somewhat ridiculous oversight really.