it is quite easy you just haven't had the time to go through your setting:
"Open Windows Update by clicking the Start button Picture of the Start button, clicking All Programs, and then clicking Windows Update.
In the left pane, click Change settings.
Choose the option that you want.
Under Recommended updates, select the Include recommended updates when downloading, installing, or notifying me about updates check box, and then click OK. Administrator permission required If you are prompted for an administrator password or confirmation, type the password or provide confirmation."
or you can go to microsoft for the full page
http://windows.microsoft.com/en-us/windows/turn-automatic-updating-on-off#turn-automatic-updating-on-off=windows-vista