My admin account stopped working (a window popped up about a "registration error?") and for some reason it's gone now. Completely gone. Fortunately, my guest account saved documents from my admin account. Now, I can't make any changes to my computer, and I certainly can't make a new account. I've looked up the problem and I've tried using the command prompt to create a new account, and... nothing happened. A message popped up that said something about insufficient privileges. Please, help!