Im havin a similar problem
I pwn a copy of XP prof (seriously)
I got it from a class i took, got to download it and burn it, and they e-mail'd me my key
anywho, lost the CD
tried installin with my bros store bought XP cd, and i put in MY cd key
and it says "invaild"
which is a bunch of pewp
im currently running XP "not register'd" on my bros CD key
isnt there a way to change yer CD key in the registry? I dont want somethin bad to happen to my bros activated windows on his comp, he will beat me....