As usual I left my computer running overnight. This morning I turned on the monitor to see a default Vista user account instead of my own profile. But the Start menu showed that it was logged in as my own account!
My Documents and all other profile folders were empty, but the files still existed under the C:/Users folder. I added a few basic icons (Firefox etc) to the desktop while searching Google for answers. One suggestion was to log out and back in. Doing this brought me back to the same default account settings--and the icons I had added were gone again.
I rebooted, and this time everything came up normally. My old profile was just as I left it, apparently none the worse for wear.
Checking uptime showed that it the PC had rebooted at 5:40am. I was on my way to work, so didn't take the time to check the event log to see why. Will check that and edit that in later.
Has anyone else seen this behaviour before?
Or know what caused it?
Is it likely to happen again?
Am I in danger of losing data?