Make sure the video card is properly seated in the agp slot. Do you get any video at startup for the bios load? Does you mobo and cpu act as if the bios is loading properly? If the mobo has onbaord video, pull the agp card see if you get video that way. Probably is the Nvida card not the mobo.
Noli Nothis Permittere Te Terere!!
EVGA 680i, Dual EVGA 8800GT'S (650/950), 4 gigs OCZ DDR2 1066, Intel Q9450 at 3.8 Ghz, Koolance Water Cooled, Dual Plextor16x DL DVD+/-RW. Dual WD 250gb 16mb Cache Sata 3.0. 3DMark06 score = 19,168.