It's a classic issue with many discussions. Put this on google.
Windows XP Corrupt Profile.
See how Microsoft deals with this one.
I was playing around with my user accounts due to some password issues. I created a new user but when I try to switch users I am unable to get back on my desktop. Now I cannot even get to the original user's desktop even tho there is no password on it. When I try to switch it tries to log on to the desktop but logs off right away. Any ideas?