Need more info. Was your computer a member of a domain, and did you change
it to a workgroup? If so, you'll need to take it back to the office and ask
the domain admin to rejoin it to the domain.
If that isn't it - what do you mean by 'there are no users' ? What exactly
did you do?
Note - posting your valid e-mail address in a newsgroup post, or in your
news account settings, is a surefire way to get spam and SWEN and other
viruses sent to you....see
http://www.mailmsg.com/SPAM_munging.htm for help
in the future, but note that now that your address is out there, there's not
much you can do other than changing your address.