To follow up on last night's post. Things seem all fixed without me doing anything.
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.