Screen blanks when using navigation buttons

This is a strange problem. When navigating in IE6, if I click and drag a
slider to scroll a window the screen will blank and within 10 seconds the
indicator LED on the monitor will change from green to yellow. No mouse or
keyboard activity will restore the screen. If I hit control-alt-delete
within the 10 seconds that the LED is still green, the system will do a warm
boot. If the LED has changed to yellow, I must reset to regain the screen.

This behavior is most predictable on the Windows Update (WU) site. The
scroll slider blanks the screen every time. On another site,
start.earthlink.com, the links sometimes cause the screen blanking. It also
happened off line while I was typing this message into Outlook Express, when
I clicked the maximize button.

I am running a freshly re-installed Windows 98 SE with all of the updates
from WU installed. I am running a vintage 2000 ABIT VT6X4 motherboard, 500
MHz slot 1 Pentium 3, and a vintage 2002 Maddog Multimedia Predator MX 440
(nvidia g-force 4) video card. Granted this is fairly old equipment, but it
had been highly reliable until I replaced it with a Gigabit motherboard and
Athalon processor (Christmas presents) which had other issues. When I
reinstalled the ABIT board this problem began. The motherboard has new bios
and drivers for the integrated peripherals and the video card has new
drivers. Since the symptoms seemed like an Automatic Power Management issue,
I turned off all APM functions in the BIOS and control paneldisplay
dialogs. The problem persisted. There are no other issues with the system.
In the intervals between screen blanking the system is very stable and fast,
for a 500 MHz PIII.

I am sure the video card is the culprit, since the symptom followed the card
into the setup with the Gigabit motherboard. Has anyone else experienced
this problem? Is there a bios or firmware in the card that can be flashed?

Thanks,

Phil M