Go to Start, then All Programs -----> Accessories -----> Command Prompt -----> and finally click Run as administrator. Continue if you receive a notification (User Account Control notifications can be disabled).

Type or paste the following command at the prompt:

net stop wuauserv

ren %systemroot%\SoftwareDistribution SoftwareDistributionold

net start wuauserv


If that doesn't get it done, then follow the steps below to re-register the files responsible for Windows Updates.

http://support.microsoft.com/kb/971058

Hope this helps.

Grif