To disable onboard video simply right click my computer, choose properties,
then the device manager tab as show in the above picture, Next find
the item you want to disable and double click on it. Before the red
x was there there was a yellow exclamation. On the General tab you
will see a line that says "Disable in this Hardware Profile", make sure
the little box is checked off it it is then you will be disable.
I did notice that in the earliest Win 95 version that the red x does
not appear for some people, the video apppently just has the yellow exclamation
and the red x does not show up.
The first time I tried to boot the screen was black, I then examined
the video card. I pushed on it in the PCI slot to make sure that
it is in place. I re-tightened the cable and all, I started it back
up and still nothing. It turned out I forgot to reconnect one of
the cables. You would think I would know better, but hey easy mistake.
Moral of my story, recheck everything again if you are having trouble.