Vista Restarts by Itself & Apps Are Restored

We have been using Windows Vista Business RTM and me and two of my colleagues
have experienced this behaviour, which has happened to each of us once.

What happens is while you are using your computer, Vista performs a restart,
then restores all your apps to their previous state. It's really bizarre,
because shutdown and subsequent startup are normal, in the sense that they
don't include undesirable behaviour like errors or a blue screen. What is
not normal is:

1. The fact that you as the user don't initiate the restart.
2. When the restart is complete and once you log on again, applications are
started again and restored to their previous state automatically.
3. Vista offers up absolutely no explanation for what happened. There are
no errors. No events are logged and there aren't even any critical events,
events pertaining to one app or service starting or faulting, or other events
leading up to the restart which might give a clue as to why it happened. No
alerts, popups or balloons appear before, during or after it happens.

We are all sysadmins and, believe me, what causes this is not as obvious as
it sounds.

Although this is not a major inconvenience, as it has only happened to each
of us once, it is a serious security concern. Although it's likely that it's
just initiated by Vista, I need to know exactly what initiates it and know
for sure that it is not an intrusion or malware.

Having done some research this morning, what I have found out, however, is
that Vista has an API called Restart Manager, and an updated version of
Windows Installer. These offer the facility for a computer to be restarted
after failure or updates and the apps to be restored to their previous state
automatically, but I still don't know what initiated the process.

Has anyone else had Vista restarting on them like this ? If so, let me know
here. Thanks :-)

--
Paul Anderson