Enable Dell Inspiron 580 For Graphics Board On PCI X16 Slot

For a Dell Inspiron 580: how do I disable on-board video BIOS setting so that Windows recognizes the graphics adapter (EVGA NVidia) installed in the PCIE-x16 slot? There is no direct access to BIOS settings other than high level options. Resetting BIOS password through interface and hardware doesn’t change anything. All of the Dell utilities I’ve used are useless with regard to this problem. Even though the BIOS is an AMIBIOS8, neither AMI nor Intel provide the tools. I cannot possibly be the only person to have this problem. Solutions such as “reinstall Windows”, “update your drivers”, “reconfigure WMI”, and “modify your INF files” are NOT welcome.