Go to windows update.
It should be under START > Programs > Windows Update
You will need to download all of the updates, then restart your computer. Don't stop there though, check for more updates and restart again. Repeat this process until there are no more updates available for download.
This should work, if not, just leave another post.
Alternatively, you can go to: http://windowsupdate.microsoft.com/
and download the updates. The method using the start menu just leads leads you to a shortcut for this address.
73 de KB3LSR