The video monitor is the focal point of every computer system. Almost all the information you use is passed through the monitor. For more than a decade, the VGA monitor was standard with computers in most of the world. High-definition, flat-panel monitors replaced VGA monitors as the standard, but you can still make good use of surplus VGA monitors with a modern computer system by using them as a second or dual monitor.
Power down the computer. Make sure you exit your operating system properly to prevent damage to the installation. In Windows, click "Start" and select "Turn Off Computer." This brings up a second window where you choose "Turn Off Computer" again. Other operating systems may have different power-down instructions. Follow your manufacturer's instructions.
Locate the VGA port attached to your motherboard on the back of your computer. This port is approximately 1 inch by 5/8 inch and is trapezoid-shaped. It is raised and contains 25 pinholes. If your motherboard does not contain a VGA port, use the VGA port on your video card or use the included adapter for the DVI port on your video card.
Plug the VGA cable from the monitor into the VGA port on the motherboard. Press the VGA cable plug into the port so it fits snugly and tighten the thumbscrews on either side. If you use the DVI adapter, plug that into the DVI port on the video card and tighten the thumb screws on either side. Then plug the VGA cable into the adapter and tighten its thumbscrews.
Turn the computer back on, enter the BIOS and make sure the VGA port is enabled on the motherboard. If you use the adapter on the video card, entering the BIOS is not necessary. Once the operating system has booted, adjust the video settings for the new configuration.
Do not tighten the thumbscrews beyond what you hands can do without tools, or you risk damaging hardware.