how do I move or reassign all of a user's Docs and Settings to ano

I have Win XP Pro SP2 on my laptop. I don't know if this had anything to do
with it, but one day after I installed Norton 360 v. 2 and having turned off
the computer in the interim, I discovered that I could not log on with my
usual account ID. Another admin account was still available, so I logged on
as that admin and found that my original user account was no longer listed in
Control Panel/User Accounts! I changed the computer type from a network
computer to a standalone computer (maybe this was a mistake, but I am unable
to change it back). I managed to create a new account, but could not give it
the same name as the old account. All the old account's Documents and
Settings are still there, but I cannot log in as the old account, only the
new account. Is it possible to move or reassign all of the old accounts Docs
and Settings to the new account? Or maybe make Windows recognize the old
account again? Or some other trick?
Please help. I had done a lot of customizations under the old account.
Thanks!
--
David