Random explorer.exe exits

[adg1034]

Like the title says, explorer.exe (not the physical system, just the visible windows GUI- desktop icons, taskbar, etc, though not programs I have running) randomly exits on me. I've scanned for spyware and viruses, and it seems to come up clean. This just started happening today (I'm actually writing this in Firefox with explorer.exe not listed as a process in Task Manager), and while it doesn't seem to be hurting anything, it's seriously aggravating. Does anyone know what could be causing this?

 

[xtknight]

Is there anything in the Event Viewer?

 

[adg1034]

Nope. And I don't have a XP install disc on hand either.