Changing domain on log in (XP Professional)

[Guest]

I changed the workgroup on my computer and restarted it. Now I cannot log
in; it is not accepting my user name and password. It's saying "make sure
your user name and domain are correct". How do I supply a domain during log
in?

Thanks.

 

[Guest]

I logged in as administrator but I can't see the original account in the lest
of user accounts.