Hardware:
SuperMicro Motherboard P6DGE w/dual 450Mhz PII's.

Symptoms:
While system is up and running and all appears normal, the
monitor will appear to blank, go into standby, or perhaps
respond to screensaver. The reality is that the system is
locked up and won't even respond to keyboard or mouse input.
The only option is to power down, BUT even that does not
solve the problem. When the system is again powered on the
boot process seems to hang in the BIOS ..somewhere.
Disconnecting power from the back of both computer and
monitor seems to bring it around to where it will boot
normally, however, once the system is up and running, it
will soon crash as before - even when mouse and keyboard
activity are present.

Solution: Upgrade the BIOS to Rev. 2.0 ..it's available at
www.supermicro.com.  I have had the system up and running
for more that 24 hours and have not had any recurrences of
the problem.