How to Install a Previously Declined Update for Windows Vista
Microsoft wants you to use Automatic Updates, but some of the automatic patches have caused more problems than they've fixed. To avoid these problems, you can turn off Vista's automatic updating feature. Then, once you're sure that the update is safe, you need to know how to retrieve and install any updates that you previously declined.
Choose Start→Control Panel and, under the Security icon, click the Check for Updates link.
Vista brings up the update history.
On the left, click the Restore Hidden Updates link.
Vista presents you with a list of any updates you may have declined in the past.
Click the update you want to bring back and then click the Restore button.
Vista brings you back to the window showing available updates.
Click the Check for Updates link.
Vista treats the updates you've restored as a new update and offers them to you again.
Click Install Updates.
You'll get not only the update that you skipped over last time, but any new updates as well.