Expansion slots (bus slots)) connect expansion cards to the motherboard. Expansion Cards are the devices such as a video card, network card, sound card, modem, and etc. There are five types of expansion slots; PCI, AGP, USB, ISA, and AMR. Your motherboard should have at least AGP, and PCI slots.

AGP (Accelerated Graphics Port) is designed to connect your AGP video card to the mother board and uses a superset of PCI specification to handle huge volume of video data. The key feature of AGP is its high speed interface to the main memory.

PCI (Peripheral Component Interconnect) is designed to connect general purpose devices. You can find PCI video cards, network cards, modems, sound cards, USB ports, etc.

USB (Universal Serial Bus) allows to connect multiple external plug-and-play devices. There are huge selection of devices that come with USB connection.

ISA (Industry Standard Architecture) offers limited data throughput and resources compared to other expansion slots. Newer computers do not come with ISA slots at all.

Generally, your current motherboard would have AGP, PCI, and USB bus slots. AGP video cards are capable of a higher data transfer rate than PCI video cards. For this instructions; we will use the expansion cards on their popular slot. Number of PCI slots vary one motherboard to another. Make sure you have enough PCI slots before you purchase extra PCI card. If you installing new PCI card, you should have it's drivers. If it's new card, it should come with driver CD otherwise download the driver from the manufacturer web site. Also if you connecting external device such as printer, digital camera/camcorder, etc to a USB port, you should have the device driver on a CD.