Missing user account and password mix-up

System would not boot-up after normal shutdown. I pulled the plug and
waited. Got system to boot normally, but it asked for my windows desktop
password. It would not take my password. Entered desktop via another
username (no administrator rights). Checked users on "C" drive and now see
that my profile is missing....,along with all my files from what I can tell!
Where did I go? Have I lost all my teaching lesson plans? If I reload
Windows XP, will it wipe my files ...if they even still exist? I'm stumped
about where things went. Even stranger...it now accepts my old desktop
password for a completely different user account. Since these other two
accounts did not have administrator privledges, I can't even get back in to
do anymore exploring.
--
Fred Strain