Windows Update setting is unchanged
There is a report that Windows Update settings in Vista was automatically changed to Automatic and forced reboot the machine after installing the security updates released this month.
Story at http://blogs.zdnet.com/microsoft/?p=830
The Vista here in my laptop still have the same settings "Check for updates for do not automatically download or install" and when I installed the Patches last Tuesday... I manually rebooted since it's required to continue installing the other updates.  I even took a screenshot last Tuesday on what items requires a reboot to continue with the installation.  As you can see in below screenshot.. some items has been marked as "Pending" (it means the installation of the patch requires a reboot) :
MS is investigating the issue as per the user who reported it.