I have a problem with 5 users of NT4 workstation.  They are 5 users in
a callcentre just like 1000 other users.  Their NT4 workstation will
gracefully shutdown unexpectedly after the first hours' usage.  After
it reboots itself, it will subsequently probably happen on a 20-30
minute basis for the rest of the day   :-(

If we pull the LAN cable out of the back, the problem stops.
It doesn't happen if they just log on to the Netware infrastruture,
they have to have launched the callcentre app.

I've got MEMSNAP and PMON captures from when the shutdown has
initiated, but nothing stands out.  They're patched and virus free.

The wierdest thing is that the problem travels with them from box to
box.  As if it's in their profile!!! If they move desks, or move
building the problem travels with them.

What can cause a graceful shutdown?
How can I trap it and stop it?