you connect your crt display or monitor to the video card on your computer
A video card is a computer chip you usually insert into your computer via a AGP slot inside of your computer (usually the same thing a sound card is in) the purpose of which to process images. if a computer does not have a video card the computer has to split the processing power between everything. but with a video card, the card processes the video instead of the computer, so you have better performance and better graphics on pretty much anything.