I've got a home-made system that suddenly is losing its video.  When cold,
the system will boot up to the Windows 98 splash screen and then reboot.
Sometime on the reboot, the video signal quits.  The monitor light changes
from green to yellow (as if the system was powered off).  The computer has
been running fine for the last several months, until this occurred.  The
monitor, an older NEC E1100, is known good.

I've checked to make sure all the fans are running.  I've tried the video
card and memory in another system and they work fine.  I attempted to
install the CPU in another system, but the heat sink wouldn't fit into my
other computer.  I've tried changing the AGP video card for a PCI.  I've
replaced the CPU, memory and video card in this system (one at a time and
all together) and the problem persists.

Changing the power supply helped.  I was able to get up to a protection
exception, or a Windows error msg depending on which reboot and the
placement of the sun, moon and stars.  I decided I needed to reload Windows,
but can't keep the video active long enough to do that.

Is the motherboard toast, or am I overlooking something?  Any suggestions on
what to do?

Hardware is:
Abit KA7-100 (raid is disabled)
AMD Athlon 850 (slot A)
256 MB PC-133 SDRAM
Diamond Stealth III S540, 32 MB
WD 200BB hard drive
Sony CDRW
Enlight 300w ATX power supply

Thanks!
Ron Jobe

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