Windows XP won't load user account

My sister came to me this morning with a computer problem. Her Dell Latitude 6400 w/ Windows XP 32bit won't load her user account. It gave her the error message "User account cannot be loaded" once, and since then, it loads some sort of default account (stock wallpaper, some but not all of her programs, lots of settings reverted). How do I fix this?

 

If the default account is an administor, create a new account for her and have her login with that. you will have to reload any apps that created needed entires in the bad account and copy shortcuts, etc
I would also scan the machine for malware in safe mode with whatever anti virus is loaded as well as malwarebytes free version.
If you do not want to go this route, there are alternate suggestions here
http://answers.microsoft.com/en-us/...le-error/dec1b83e-348d-4603-adec-6e86fd9e50ae

 

I would check the registry entry under

HKEY_Local_Machine/Software/Microsoft/WindowsNT/CurrentVersion/Winlogon
and check the entry next to

shell=Explorer.exe

and

Userinit=c:\Windows\System32\userinit.exe

and make sure that these entries are correct.

I hope this helps at all.