[PsYcNeT]

Does it show the BIOS/Splash screen or does the screen not even initialize?

If it works fine with the onboard, sometimes motherboards can be picky about PCI-E cards (or it needs a BIOS update).

My recommendation is to:

a) take out the video card

b) reformat it immediately with everything but the card in

c) once windows boots properly, update all your drivers/chipset/etc.

d) flash the BIOS to the latest version

e) verify it boots properly once the BIOS is flashed

f) power down, install the video card

g) turn off the on-board card in the BIOS

h) install the newest ATI drivers
I presume it should work fine after all these steps. If you hit a snag, let me know. I'm dicking around with my new laptop so I'll be online for a bit.