Comp Freeze During DXDiag Fullscreen Test (IRQs suspected)

I'm having problems running anything in full screen mode without freezing. During the non-fullscreen tests in dxdiag it works but once it goes fullscreen i'm left with a image of either the white block or the side of the cube and I have to shut down via power button. I've tried using the windows graphics drivers, the latest nvidia drivers, and an older nvidia driver. I've also tried using the newest VIA chipset drivers, and the older one. I've checked for heat and there's no problem there. When I check the IRQs of the devices, the graphics card, usb ports, onboard audio, and my network cards are showing on IRQ 9. I tried messing with the BIOS settings to make the graphics card take it's own IRQ (but this is an HP we're talking about here, so no sophisticated settings) and repairing windows xp and THOUGHT I had it fixed when windows detected the graphics card on IRQ 11, but then it went back to 9 after installed I the drivers and rebooting. Any ideas?

Specs:
1.2 ghz Athlon Thunderbird
Geforce 3 Ti200
VIA Chipset

edit: well i tried standard pc mode which put the graphics card on it's own IRQ and had the same problem so i'm clueless as to what's causing this

what sound card and os and service pack

onboard VIA audio, windows xp sp2

before xp i tried with win2k pro sp4 with the same problems

meh.. tried standard pc mode which left it on it's own irq and still froze..

Many devices being on 1 IRQ is calling PCI steering, and it has been around since Windows 98 and is pretty perfected by now. It isn't causing any issues unless you are using some really old hardware.

Have you tried swapping in another video card to see if yours is the problem? You've done a hell of a lot of software testing and it looks like you've all but eliminated any possibilities there (good job! if only most people would do that much before asking for advice ). How long has this been going on for?