The long awaited answer....

Yep, a KVM switch box was involved, but there were additional coincidences that contributed to the situation.

  1. Several weeks before, when i installed Vista on the desktop, i customized it to my favorite layouts, like the bonzai tree and the bamboo wallpaper.  (note how i did the exact same customizations on my laptop).
  2. I had the exact same folders on both machines' desktops.  Yep, i created a folder with the exact same name and contents.
  3. After having installed Vista on my laptop late that Friday evening, the switchview defaulted to my desktop.  in other words, the switchview is always on by default to my laptop, but for whatever reason that night, it switched to my desktop.  I remember thinking, "oh, i better switch it back to the laptop, because i won't remember on Monday morning and i might get confused, but i'm too lazy and just want to get out of here."

So, if you answered "a KVM switchbox pointing to another machine with the exact same customizations on the desktop and user account", you should start answering questions on the Microsoft forums!