1. Try logging on as another user with ADMIN rights

2. Try logging on in SAFE MODE
    http://windows.microsoft.com/en-gb/windows/start-computer-safe-mode#start-computer-safe-mode=windows-vista 
    http://windows.microsoft.com/en-gb/windows/advanced-startup-options-including-safe-mode#1TC=windows-7  

3. Try using SYSTEM RESTORE

    http://windows.microsoft.com/en-GB/windows7/products/features/system-restore



Other Links

http://support.microsoft.com/kb/947215

http://answers.microsoft.com/en-us/windows/forum/windows_7-security/i-receive-error-message-the-user-profile-service/38844b82-a2c1-4fa2-9802-a5318d6f7831

http://community.spiceworks.com/how_to/show/11671-resolving-the-user-profile-service-failed-the-logon-user-profile-cannot-be-loaded