Cannot get into XP

I’m working on an XP Pro computer. The guy who had this job before me uprgraded a customer’s computer from ME to XP Pro. Now when I start up the computer, it asks for a password for the user Mike. No matter what I enter, it says that the ‘specified domain either does not exist or could not be contacted.’ The catch here is that there is no NIC in the computer and there does not appear to be a domain set up. When I press ctrl-atl-del, there is no domain field, just username and password. Is theresome way to bypass this or turn it off. I just need to know how to get into XP without getting rid of the user’s files. I don’t care about the programs.