Drivers or anything to do with windows will have no impact if your system wont even post with the card in the PC.
It sounds like a bad card, but could be some other conflict. I'd also urge you to try with another brand/make power supply with nothing else but the agp card/cpu/memory. Sometimes there can be some weird 3.3v or 5v thing with the motherboard causing a race condition or amperage need that some modern power supplies do not support (Antec had a few series like this they fixed within a revision or two- dead as a doornail powering up with a certain combination of hardware).
I'd recommend yanking all PCI cards/expansion cards, as well as pulling all the ide cables off drives. I'd also disable all serial, parallel and usb ports in the BIOS, save this and plop the card in for last finger-crossing event of hope.
Basically, you want a cold start with just mainboard (with all devices disables), agp card, memory and cpu.. nothing else enabled, in the slots, drawing power or connected. If it still wont post this way, it's a bum card or conflict/incompatible.
