[quote][b]Posted by:[/b] oys i had been playing for years and few weeks ago i tried runnin halo custom edition. i got an error message saying my cd key was invalid, so i couldn't even open it up. i tried doing a bunch of things and none worked. so i bought it again. now with the new cd key i am able to play halo pc but i get the same message in halo ce. any help?[/quote] got the exact same problem. did the exact same thing.i had someone suggest messing with the registry, but im terrible with finding stuff in that. solution: buy tf2