There are many types of graphics cards, but i think your referring to different slots that they can go into, wether your card is an Nvidia or ATI there are two mainstream card slots they fit into, depending on how new or old your motherboard is, you'll need an AGP slot or a PCI-express slot (pci-express is the newer one), you'll probably need to read your motherboards manual to find this stuff out.
As for the Ram, it just clicks into the RAM slots, but these can differ to depending on the slots in your motherboard, however most computers use DDR2, but if your computers newer or more high end it might use a different slot.