Hi,
A user profile can become corrupted if your antivirus software is scanning your PC while you try to log on, but it could also be caused by other things.
A quick fix can be to restart your PC, but if this doesnt work youll need to restart again and boot into Safe mode. Do this by pressing F8 before you see the Windows loading screen and choosing Safe Mode from the menu that appears. Safe Mode logs you into
the built-in Windows administrator account.
Please follow the link below to fix corrupt user profile:
http://www.pcadvisor.co.uk/how-to/windows/3495216/how-fix-corrupt-user-profile-in-windows-7/
In addition, here is a blog regarding to corrupt user profiles, you may also refer to it:
Mythical Creatures Corrupt User Profiles
http://blogs.technet.com/b/askds/archive/2010/10/20/mythical-creatures-corrupt-user-profiles.aspx
Regards,
Yan Li