Look at what Microsoft offers to fix those (they don't!) at http://support.microsoft.com/kb/811151
You may or may not see the corrupt profile error message.
When I click on my name on the logon screen it says that it is loading my settings but then it goes back to the logon screen in a loop.
My PC runs Windows XP Pro and it was booting without having to log on until the lastest security updates were installed. Now the PC presents a logon screen, and asks me to click on my name. When I do so, it says that my personal settings are being loaded, then a mesage comes up saying that windows is logging off and saving my settings before it returns to the logon screen. When I click on my name again, Windows repates the process in a loop.
I can center Safe Mode with Networking and am presented with the Administrator account and my own user account. I can logon to the admin account. I have checked the system with with AVG virus scanner and the online Kaspersky virus scanner and the spybot s&d, ad-ware, windows defender spyware removal tools, all of which found nothing.
I thenk used Add or Remove Programs in the Control Panel with its Show updates option emabled to remove microsofts security updates, but the windows genuine advantage (WGA) update couldn't be removed and the problem remains. I've tried using System Restore and a repair install, but it still doesn't let me in