Local corrupt file

Seems you have a corrupt user profile.
What I suggest is to create a new user login in Windows, login as that, restart your computer, backup all your files you want from the old profile from C:\Documents and Settings then delete the user profile from Windows, then login again and recover your files from the backup.

There are a number of steps you have to do, but if you Google, "creating a new profile +win xp", I'm sure someone's written an article on how to do this already.