CUV-NT on-board video

I have a friend that has a HP 8760c (I know,she bought it without asking first) that has an OEM Asus MB marked CUV-NT with a Vanta on-board vid chip,VIA chipset,PIII733,and Award BIOS. It will boot after about 20 or so attempts. If it fails to boot, the beep code is 1 long-2 short. Award beep code for bad video. When the system does finally boot it runs fine. I want to disable the on-board video and stick a different vid card in it to see it it cures the problem. There is no option to disable the video in BIOS, and no jumper on the MB to disable it either. The only option i see is to disable the on-board chip from device manager and stick in the new card and see what happens. I was just wondering if anyone has any experience with this MB or has another option that I've overlooked. Thanks.