[Crpl. Crunch]

I'm having problems connecting to a game. I have the patch installed correctly I think. What's happening is when I try to join a server it says my CD key is invalid. I typed it in the space in the multiplayer options menu, went back to join a server and the same thing happened. I've uninstalled it and reinstalled it and it still does it. By the way, it says that my CD key is correct in the options menu but it still doesn't work. There is nothing regarding this on their website.
I'm asking on this forum because I don't want to join another just to fix this problem. Any help would be great, thanks!