your motherboard is unusual in the fact it has an agp and a pci-e graphics slot although the pci-e only runs at x4 mode, normally it runs at x8 or x16 mode i dont know if that has any bearing on your troubles, the latest bios
driver for your board is 2.20 which seems to add patches for ati graphics cards, i know your'e running an nvidia card im sorry im all out of ideas now maybe someone else will be along later