can you tell us what's the lastest update that was updated to
your computer?
you can do so by:
start
type in windows update
@ the left hand side - view update history.
see the lastest update that caused it.
take note of the update numbers eg: KB1082820
Update for Windows Vista (KB955020)
Installation date: 7/13/2008 12:10 PM
Installation status: Successful
Update type: Important
Install this update to add words to the English and German standard
dictionaries. After you install this item, you may have to restart
your computer. This update is provided to you and licensed under
the Windows Vista License Terms.
More information:
http://support.microsoft.com/kb/955020
Help and Support:
http://support.microsoft.com