There used to be a 'Level Up' hack for COD4, not sure if its still floating around somewhere ..... but be warned, I do know people who were banned from some servers for using it!! Even tho it is a 'hack' its not a multiplayer hack, meaning it gives you no gain ingame except for obviously ranking you up to 70 and giving you all the extra weapons, its not an aim bot or a wall hack.
Unfortunately, when it comes to COD4 you MUST always back up you MP Profile, it is not saved online, if you uninstall without first backing up your profile then you have to start from the beginning again ...... but I guess you are already aware of this.
