Out of sync error

[tronster26]

Hey everytime i join a game and try to play it kicks me out as soon as i try to place a unit or after about 5 seconds. it says out of sync 0:cd. I already checked my resource folder and everything is how its suppose to be. I cant uninstall my game because i cant find my cd key so if anyone knows how to find ur cd key in a folder or if you have any solutions to my problem please just post. Thanks