Problem logging on to existing Windows user account

I have an emergency with my computer!
I just turned My IBM laptop on and when I logged on to my user account,
it gave me a warning message, something like, "your local profile can't
be updated (or located)," and now when it opens my Windows account,
none of my existing stuff shows up, nothing that's saved shows up (and
there are thousands of documents, many not copied anywhere in their
final form). It's like working with a brand new computer, with
original settings. Is all this stuff still there somewhere, and how
can I retrieve it? What should I do? I'm having a total panic attack
over this, so I'd really appreciate your help.