Both laptop and desktop computers can run more than one monitor. Connecting multiple monitors to a computer system increases the desktop workspace, making it easier to multitask. To set up dual monitors on a computer, connect both monitors to the computer's available video ports. Not all computers come with multiple video ports, so you may have to purchase extra equipment to set up multiple displays. After connecting both monitors, configure the display settings in Windows.
Connect the first monitor to the VGA, DVI or HDMI port on the rear of the computer. VGA ports require 15-pin connectors and DVI ports require 29-pin connectors. HDMI ports look different from VGA and DVI ports in that the connection resembles a USB port. Plug the monitor's power cable into a wall outlet or power strip.
Turn on the monitor, power on the computer and sign in to Windows. Right-click a blank area on the desktop and choose "Screen resolution" from the contextual menu.
Click "Resolution" and select the recommended setting. Click "Apply."
Connect the second monitor to the computer. Most modern video cards include both a DVI and VGA port, allowing you to hook up two monitors, but some computers -- laptops, in particular -- only have one. If your computer system does not have more than one video port, connect a USB video adaptor to an available USB port, and then connect the monitor to the video adaptor. Connect the monitor to power and turn the monitor on.
Click "Detect." Select monitor "1" and click "Identify" to determine which number is assigned to which monitor.
Select the number assigned to the second monitor. Click "Resolution" and select the recommended setting. Click "Apply."
Select the number assigned to the monitor you want to use as the primary display. Check "Make this my main display."
Expand "Multiple displays." Choose "Extend these displays" to extend the desktop onto the other monitor. Choose "Duplicate these displays" to view the desktop on both monitors.
Click "Apply," then "OK," to save your settings.
If you have a laptop computer and want to connect a second monitor to it, look for a video port on the side or rear of the laptop. Some laptops come with function shortcuts, like "Fn" and "F7," that allow you to swap between display settings. If you have a DVI port, but only VGA monitors, connect a VGA-to-DVI adaptor to the rear of the computer. If you have an HDMI port, but neither monitor uses HDMI, connect an HDMI-to-VGA or HDMI-to-DVI adaptor to the computer.
Not all motherboards support dual monitors. Go to your computer or motherboard manufacturer's website and review your model's manual to confirm the computer can run multiple monitors. An HDMI monitor cannot connect to a DVI or VGA graphics port.