Xp will only log on to a temporary user account

For some reason Windows (Xp Home sp3) has started logging me on to a temporary account. If I log off the screen where I select an account appears. My regular account is the only one in use and it appears there as it should. I click to choose it and I log on but the desktop is not mine and the Windows Tour icon is now in the taskbar. When I click "Start" at bottom left, my regular account name appears at the top of the menu but none of my settings or files are in effect or available. In My Computer under Documents and Settings, the accounts listed are Administrator, All Users, my regular account and a new one called TEMP.
I have no idea why this is happening or how to fix it. I ran checkdisk and it fixed a bad cluster in ntuser.data. I don't know enough to judge whether that would be a related issue or not and, at any rate, the problem persists. Any advice appreciated.
Thanks.

 

That could have very well been the problem. Often times malware can do this too. Can you get to the user section(in control panel) and change the settings back?

Are you getting an error message from windows?