:lucifer
As i said before, just call diablo tech support and ask for a new cd-key, however, because i think that you just either gave yours out or are using a downloaded version of diablo, you can't. I apologise if i am incorrect, but still, it is unlikely that your CD was stolen, besides, who is going to post thier cd-key, if all you want is the single-player then just search for one, else you are skrewed, at most you can maintain a connection for one hour before someone sends you a kill command, while using a public cd-key.