I apparrently developed this problem myself...while I was at a funeral.
When I left the system was running just fine, but when I came back, and the system was sitting there with nothing but the background image displayed, OBVIOUSLY something wrong, so I rebooted.
System boots normally, "appears" to load explorer, then the second I move the mouse BLAM! All the icons disappear, as well as the start button, bar, etc.
I give it the three-button-salute, run a new copy of explorer.exe since it doesn't appear in the task list, and from that point forward, explorer loads, crashes, loads, crashes, loads...mildly annoying.
Since I've only got one account on that machine, there's no admin account to work with, so I'm at a bit of a loss as to what to do...never seen this before!
Interesting that even running extra copies of Explorer doesn't help, since if you click on ANY icon, BLAM! Crash and restart explorer...if you load anything from the menu, BLAM! It restarts explorer again.
Maybe I'll have to replace explorer.exe?!