user profiles

All of the sudden the user profile I have been using to login is gone. I can
still see the folder under documents and settings. I can login through the
admin user account but cant create a new user.

the user accounts screen looks different than other computers i have, it
lists the user names and domain and group, and when I go to add another one
it says. "the user "myusername" could not be added to the administrator group
because "domain\username" does not exist."

I tried to restore to an earlier point but no luck. How can I either create
a new user and copy all the info over from my old account or find the one
that is lost.
thanks