Posted by Loyen_
Start->Run->regedit (press enter)-> HKEY_LOCAL_MACHINE\SOFTWARE\Electronic Arts\Electronic Arts->game (then a tree folder which would be named something like ergc or whatever, don't have bf installed but C&C3) and you'll find your key without -'s in one of the reg files.
I already did this. Huge length of characters, both numbers and letters, like 50+ different letters pop up instead of the CD Key. I have no idea why.