Try performing a vista restore:
Close and save any documents that you may have open.
Click on the Start button to open your Start Menu.
When the Start Menu opens click on the All Programs menu option.
Click once on the Accessories Start Menu group.
Click once on the System Tools Start Menu group.
Click once on the System Restore icon. After you click on the icon, if a User Account Control window opens you should click on the Continue button.
Try applying an earlier restore point before you started getting this error