Other user is useless

I got a vista computer that was pretty badly infected with many diff viruses and as I was trying to remove them it blue screened and not when I rebooted even in safe mode the only user that comes uo on the log on screen is "Other User" and no matter what I put in there it is always wrong and I get the error message that I can't log on to the domain (this computer is a stand alone not connected to internet what so ever) and it has never been in a domain. I try Admin, Guest and the other user in that is in it and I always get the same error message. Any sugesstions?