New video card issues

i have a internal video card that came with my computer when i bought it, an integrated intel express chipset g33/g31 pci express video card but it sucks....bad, so i got a new one, along with a power supply, but when i booted up it went total black screen, nothing worked. its in the right slot and plugged in right i know that, but i cant even install my drivers to make it work cuz when its not plugged in it works just fine, but cant find the new card. i have a coolermaster gt 750w and a gtx 450 video card. how can i fix this? what P# goes into the video card to make it work? it works just fine without it plugged in...