Geforce GTS 250 Not Recognized

Hello,
When booting the computer up with the monitor plugged into the gts 250 i get a blank screen, when i boot it up with the onboard video it works. the video card is not found by windows device manager, and am unable to install the device drivers.
I am running a intel i3-530 with a gigabye h55m-s2h motherboard, 4 gigs of 10666mhz ddr3 ram, 850W psu,
i have tried clearing the cmos, and i have changed the settings in the bios so the pci-e card is the primary, can anyone help me?