There are two main types - AGP, which is now the most common, and PCI. All modern motherboards include an AGP slot, but PCI graphics cards still exist and are often used to drive second (or third) monitors. There were once VESA and ISA graphics cards but both of those standards are now effectively dead.. .. .I'm guessing you have an older motherboard which just has PCI and ISA slots? Return the card from whence it came and get them to give you a PCI one. . .. .If you can let me know what your motherboard is I may be able to help further.