1.- First you will need a copy of COD4:MW (they are all the same disk or digital).
This is usually done through torrents (if your unsure what torrents are read my torrents article). There are several copies floating around out there, some with cracks others without. It will not matter if you download one with a crack or not as you will not be using that particular crack, if the crack is a separate file i recommend not downloading that file, just COD4. 2.- You will need a serial.
If the torrent you downloaded came with a serial for the game do not use it, as it has likely be used by many and has already been blocked by punkbuster. Thus you will get a "Global Punkbuster GUID BAN 50a15a0a" later on when you try to play multiplayer. What you need here is a Cd Key Generator thus ensuring you will have a key that is unused and not banned. By the way your stats in multiplayer will be linked to your CD Key so once you start playing you will not want to change your CD Key, hence facing a reset of you hard earned stats. You can download a Cd Key Generator through torrents again, some copies of COD4 will come with a Generator.
3.- You are ready to install. Install the game with a generated key.
4.- Updating your COD4. Based on whatever torrent you downloaded you will have a different version of COD4 ranging form v1.0+. It doesn't matter which version you have because they will all be out of date. Lucky the update pack 1.6 includes all previous update packs [Full update]. Don't bother downloading versions 1.2-1.5 they are included in the 1.6. You will how ever afterward have to apply update 1.7. do not skip update 1.6 and go directly to 1.7,[incremental update] - does not included previous update content.
You will need:
*Update v1.6 found here - http://www.gamershell.com/download_27186.shtml
*Update v1.7 found here - http://www.gamershell.com/download_28304.shtml
5.- You are now ready to crack. The crack you will be using is a single player crack. Use it even if you do not plan to play single payer.
You will need:
*SP Crack v1.7 (iw3sp.exe) one copy can be found here - http://rs480.rapidshare.com/files/175038091/COD4MW_EPC_pack.rar
DO NOT TOUCH THE iw3mp.exe FILE (multiplayer)
6.- Now you will need to download Qtracker. Qtracker is an external server listing program that will allow you to add servers besides those listed in the COD4 multiplayer screen. I recomend this service regardless of what games your playing cracked or not as it consolidates the server lists for all big multipalyer games and makes for a better online experice overall.
You will need:
*qtracker4xx.exe it can be found here - http://www.qtracker.com/
Qtracker is FREEWARE