Click on Start and select Run
Type “gpedit.msc”
Navigate to Local Computer Policy | Computer Configuration | Administrative Templates | Windows Components | Windows Update
On the right hand side, select and double click on the entry entitled: “No auto-restart with logged on users for scheduled automatic updates installations”
Select the option “Enabled” and click Apply and/or OK
And voila!
NB: Don’t forget to restart your computer from time to time ;)
Links:
[1] http://pulse.veltsos.com/category/it/general
[2] http://pulse.veltsos.com/category/it/software/software/os/microsoft
[3] http://pulse.veltsos.com/category/it/tweaks
[4] http://linux.philosweb.com/drupal5/files/image_2_79.png
[5] http://linux.philosweb.com/drupal5/files/image_4_30.png
[6] http://linux.philosweb.com/drupal5/files/image_6_12.png
[7] http://linux.philosweb.com/drupal5/files/image_8_8.png
[8] http://linux.philosweb.com/drupal5/files/image_10_4.png
[9] http://linux.philosweb.com/drupal5/files/image_12_1.png