Cannot Connect to Domain (and don’t want to)

My neighbor has a problem that he asked me to look at. When he logs onto his Windows XP Home computer, it tells him it can’t connect to the domain. That has never happened before and the domain name is something very unique to him – and similar to his password.

He tells me he didn’t set up a domain – and he wouldn’t know how, either. Is there any way a domain could ‘accidentally’ be joined?

Is there a way to remove the computer from the domain without being able to log in? The Administrator log on still says it can’t log on because it can’t connect to the domain. Since it’s the home version there isn’t the traditional drop down menu to log onto only his computer.