NVIDIA 8800 GTS Failure?

So I've got a bit of a wierd situation that I need some more advice on. Here's a short summary of the problem:

Turned my computer off normally about 3 hours ago. Just booted it up and it sits for around 15 - 20 seconds before posting. Then it does and goes through boot up process, but the monitors receive no signal (two monitors both on DVI to HDMI). I've tried unplugged the video card from the PCI-E slot, booting, then turning it off and putting it back in and no dice. Installing drivers doesn't help as it can't find the hardware...doesn't show up in the device menu, and scanning doesn't find it either. I'm using onboard video at the moment...I assume this is a dead graphics card, but its relatively new (~6 months). Could it be my PCI-E slot? The fans on the graphics card are running...but that doesn't mean much I don't think. Here's the specs:

Video Card: BFG NVIDIA 8800 GTS 512mb
PC Brand: Self Built
Motherboard Brand: Gigabyte
Motherboard Chipset: S Series Socket AM2 GA-M51GM-S2G
Processor Type: AMD Athlon 64 X2 5000+
System Memory: Geil Ultra Fast Dual Channel 2048MB PC4200 DDR2 533MHz (2
x 1024MB) and two gigs of generic ram
System BIOS: Award Software F2 08/09/2006
Nvidia Driver: 6.14.11.8122 and I tried the original drivers that came
with the video card.
Operating System: Windows XP Professional - 32bit
Power Supply: 6 months old, 700w single 12v rail 38 amps ULTRA power supply.

Now, full disclosure here, this system is 3 years old. I originally had a BFG NVIDIA 9750 GTX in there (I think) and it died after about 2 and a half years. It worked but dots were appearing on the screen in random places. I RMA'd it and got this BFG NVIDIA 8800 GTS. At that time I also bought a the new ULTRA power supply in case that was the issue.

If you know someone that has a computer to test the card in try that first,if it works it's your motherboard. I am assuming that this card worked before in your machine.

Just to follow up on this, I took it to a friends place (the gfx card) and it works perfectly. No problem at all installing and setting it up, so its definitely a PCI-E problem on my mobo.