Anyone ever seen a Music for disappear and re-appear later?

Last night when I logged onto Vista I saw the following thingss...
1. Plugged in to sync iPhone but it wouldn't sync since itunes was "empty." The itunes database was gone from the Music folder so itunes had to start fresh. The music file were still on the server the but the itunes data was gone.
2. The Documents and Pictures buttons on the start menu did not open anything. The Music and Games buttons did open to the proper folder. The properties of Documents and Pictures were empty as if there are corrupted or something.

I was really panicked because we have a ton of album art and playists in that itunes directory.

When I got home from work I noticed that the computer had rebooted itself during the day. When I logged in again the iTunes database was there so iTunes loaded everything just fine, the start menu shortcuts worked and all was well.

It's as if when I rebooted the laptop in an attempt to clear up the internet connection problem Vista didn't load or find my user profile properly. It makes some sense to me that the start menu shortcuts might take a bit flip and not work 1 time, but the vanishing iTunes database is something else. Somehow the entire "Music" folder was different for just that 1 logon session.

It's not to often you get a second chance. I have now backed up the music folder and I'll continue to investigate.