here is a photo (yes I know my PC is dusty): http://img228.imageshack.us/img228/7258/1003787y.jpg
the model of the motherboard itself is the amethyst-m mother board which came with an ati radeon xpress 200 series graphics card.
now I have been told by someone else that it is a PCI-E but I just want to make sure. Also is it the black or white slot that I have to insert the graphics card into.
****Also wondering if the type of RAM in the graphics card matters, I ask because my computer is 4 years old and takes ddr but most graphics cards have ddr3*****
Your motherboard is a MSI MS-7184 made for HP & does have a PCI-E slot for a PCI-E 16X video card. You did not list what model the HP was so I dont know how many watts/amps you power suppy has but if your going to be buying a good video card you might need to upgrade the power supply. The VRAM on your new video card does not need to be the same as your PCs systems RAM. So even if your PC uses DDR2 & the video card uses GDDR3 its fine, no problems. Make sure your power supply has the watts/amps & PCI-E connectors(6 pin, 8 pin or both) to run the card is the most important thing to have right.