Fitting graphics cards and other expansion cards, such as wireless adapters, TV tuners and sound cards, is a simple affair. To insert a graphics card, locate an empty PCI Express xl6 slot and remove the metal cover that backs onto it perpendicularly. Note that there are different sizes of PCI Express slot - xl, x4, x8 and xl6 - so be sure to pick the one that fits the part you are adding. Gently push the graphics card into this slot until it fits snugly and fasten the rear backplate with a screw.