Skimmed through the previous post kinda quickly. So this may be a repeat.
Do you have onboard video at all? Or just seperate video cards?
Try again to set your display adapter to "standard vga". From what I have read this must be done first. After this is done. Insert video card and reboot machine and see if it is detected and install drivers.
Good luck
HP Pavilion a1710n
AMD Athon 64 X2 Dual Core 4400 (2.2ghz)
320g Hard Drive
1g DDR Memory
DVD with LightScribe
9 in 1 Media Card Reader
NVIDIA GeForce 6150 LE (Onboard Video)
RealTek Onboard Sound (5.1)
Windows Vista Home Premium