Vista Event Notification service fails, logs user off immediately

This has only happened once (this morning), so I am not completely freaking
out yet, but given that I just got admin access back on my Vista machine
(see my UAC post for details), any kind of security issues like this get me
paranoid. Basically, I restarted my machine this morning, and when I logged
back in, I got an error message that the Event Notification service failed
to start, and then Vista immediately logged me off. Thankfully, I was able
to log right back in, but I'm curious if this is something I shoud worry
about ot the extent that I run some troubleshooting before I next reboot my
machine.