You were a little vague on what exactly you mean, but I'm going to hazard a
guess and assume you're talking about your email, in particular your Outlook
Express? You didn't mention a version number, but since you're posting to an
XP newsgroup, I'll assume you're running Outlook Express (OE) 6.
In OE (not a mail message), go to Tools --> accounts. Go to the Mail tab,
and find the email account in question. At this point, you have a few
choices - you can either highlight the account you want, choose properties
and make changes to this account to reflect your new information, or you can
choose Add --> Mail. This will start a short wizard that will allow you to
put in all the new info you want and create a new account. When the account
is made and verified to be working, you can delete the old account.
I hope this helps. Post back if I'm on the wrong track or if you mean
something else.
Also, when posting in the future, try to be as specific as possible -
including any errors you're getting, the program name and version causing
the error, etc.
Patrick Pitre