To add more to my previous message.. My Administrator's documents and all my files are still on the hard drive in the Administrator folder, but i can't log in to it.
I left my computer on left night and my screensaver returns to the login menu when it's deactivated. When the login screen loaded this morning my Administrator Account is gone. This is the account that I use the most and I was playing games on it last night. I installed nothing yesterday.
Windows XP Media Center Edition
HP Media Center PC m380n