Now this really is a mystery. I first read your answer above whilst in XP, so I rebooted to get into Vista. Got a BSOD and immediate reboot (too fast to read) then got in to Safe Mode OK. Nothing untoward in the Event Viewer so assume the BSOD at least was a hardware glitch as I then booted into regular Vista as usual with no problems.
In the event viewer there are a few exclamation marks but nothing serious around the time the above happened or when my BSOD happened...very strange.
I looked in ACEEvent, Applications, Security, Setup, and System.
I noticed that the "Forwarded Events" (to Microsoft I assume) is blank even though I have opted to report all errors. Unless that log is for something else.
So CG, your guess is as good as mine right now!