PCI express port does not work?

Hey, I've had my HP computer for a few years now and about a month ago I got my PCI express video card replaced with a basic PCI one, but I had to upgrade so I purchased and installed an EVGA GT 220 PCIe into my PCIe port but it doesnt work i dont get any signal to my monitor. I tried different DVI cables so I know thats not the problem, I also used VGA cables and it still doesnt work! it seems that only my PCI port works but not my PCIe. I also got a new power supply installed, i switched out the ram memory stuff and still no luck. could it be that my PCIe port is messed up? how could i go about getting this fixed?