(Geek)Fried my dam mother board

[bparker]

Ok, here is the background on what happened.
I "was" running XP Pro 32bit OS great supporting 3 monitors for over a year with my HP xw8200 workstation. I had several different primary video cards in this PC and previous PCs and this setup worked great. I "was" using an old Voodoo3 PCI video card in a pci slot as my secondary video card to support the 3rd monitor. Again, all "was" well and working great in that config.
Well, I decided to move to XP Pro 64 Bit OS and put in a new drive etc.. and installed the OS. OS went in fine but I noticed that the the 3rd monitor had no video - then realized that the Voodoo card was not supported nor would ever be as it didnt have any 64bit drivers available.
So, I started trying a couple of different newer PCI video cards as secondary cards to support my 3rd monitor.
Yesterday's config that blew me up:
1 x BFG Nvidia 8800 768 meg PCI-Express video card.
1 x ATI VisionTek 1300 PCI card
Installed said secondary ATI card (booted up fine with both video cards in the PC) and after the OS detected the card and the drivers were installed. I rebooted. After that the OS would blue screen and reboot while attempting to boot. Did this many times and I tried to use "Last known good" and it still blue screened and rebooted. (arg)
I shut down the PC and took out the ATI card and tried a gforce 5200 PCI card in the secondary slot and when I attempted to power on the PC the computer would no longer post (aka would not show the BIOS screen).
I tried different PCI slots to no avail as I could NOT get video regardless.
I then took out the secondary card and tried to boot with just my primary BFG 8800 in the PC. Nope, nothing, nada no video not even the BIOS.
I then took all video cards out and tried a different old PCI card (Asus Generic) and got no video or bios.
Tried other PCI and PCI express video cards and got nothing.
Called HP and confirmed the worst - the mother board was fried and they are sending me a new one overnight (yay for HP).

Has ANYONE sucessfully installed and ran TWO newer video cards in a XP Pro 64bit OS?
If so please post which cards and what types (IE Pci, PCI-E, AGP, Etc)