used with permission from Microsoft at Home

You can never have enough screen space. Instead of buying a larger computer monitor, you can buy an inexpensive second monitor or make use of a spare one and connect it to your computer (if you’re using Windows 7 or Windows Vista)—instantly doubling your desktop space.

Dual monitor setup checklist

There’s a good chance you already have everything you need to set up your second monitor.

If you need more detail about the necessary equipment, you’ll find it in the Know your equipment section.

  • Two monitors (one, if you’re setting up a laptop), which may be flat-panel LCD monitors or CRT monitors or one of each—it doesn’t matter. You can even use a TV screen as a monitor. If you’re going to buy a monitor, there are many points to consider in addition to the price. For example, picture quality, screen size, screen resolution, compatibility with your computer port, higher contrast ratio, and richness of color are some of the most important factors.
    Although we refer to two monitors in this article, you can use more than two as long as you have the connectors available on your computer.
  • Two monitor cables to connect the monitors to the computer (one for a laptop). These need to match the connection types available on your computer.
  • A monitor connection on your computer for each monitor you want to connect. These may be Digital Visual Interface (DVI) connectors, Video Graphics Array (VGA) connectors, HDMI (High Definition Multimedia Interface) connectors, or S-Video connectors for using your TV as a monitor. The connections will need to match the monitor cables. These ports connect to video cards in your computer. They are usually located on the back of your desktop computer and on the side or back of your laptop computer.
  • If you don’t have the connectors you need for your monitors, you can install a video adapter to change the connector type, or, if you’re using a desktop computer, you can replace your video card or install additional cards. This involves opening your computer, so you may want to seek assistance from a local computer retailer.

Know your equipment

The following table provides more information about the components for setting up an extra monitor.

Equipment Description More information
LCD (Liquid Crystal Display) monitor LCD monitors are thin, light, and high-resolution.
CRT (Cathode Ray Tube) monitor: An older, bulkier monitor, still popular because of its low cost CRTs are larger, heavier, and require more desk space but are cheaper than LCD models.
VGA (Video Graphic Array) port VGA ports are the most common computer ports, using an analog system to transfer display data.
DVI (Digital Video Interface) port A DVI port provides a high-quality display using digital techniques to transfer the display data.
HDMI (High Definition Multimedia Interface) port HDMI ports are the interface standard used for audio-visual equipment, such as HDTVs or home theater systems.
S-Video port An S-Video port is one of the most common ways to connect computers to TVs.
Monitor cable A monitor cable carries information in graphic form from the computer to the monitor. The connectors on the cables you use must match the connectors on your computer.
Video adapter cable or converter You’ll only need a converter if you’re trying to connect a computer with one type of graphics card, such as VGA, to a monitor using another technology, like DVI.

How to set up your second monitor

Connect the monitor cables

When you’re ready to connect the monitor cable to the connector on your computer, make sure the monitor is plugged in and turned on. Your computer should automatically detect the second monitor, although you may have to restart your computer first.

When your computer detects the monitor, it should also automatically detect and apply the display settings appropriate for the monitor.

Configure your displays

You may want to adjust display settings yourself.

The settings shown here are for Windows 7, but they are basically the same as those available for Windows Vista. If necessary, you can drag the monitor icons so that they are arranged in the same way as the monitors on your desk. Click Identify to verify which monitor is 1 and which monitor is 2. You’ll see the numbers appear on your monitors.

Under Multiple displays, you can also adjust what you see on the second monitor. You have the following choices:

  • Extend your displays. This spreads your desktop over both monitors and lets you drag items between the two screens. This is how most people use two monitors, and it’s the default setting for desktop computers. After your monitor is set up, you can use your mouse to grab the title bar (the top portion) of a window and drag it to your new display. If a window does not move when you drag it, double-click the title bar first, and then drag it.
  • Duplicate your displays. This displays the same desktop on both monitors. For a laptop, this is the default setting. This is useful if you’re giving a presentation with your laptop connected to a projector or large monitor.
  • Show your desktop on only one monitor. This is most commonly used with a laptop if you want to keep your laptop screen blank after you connect to a large desktop monitor.

When you disconnect the additional monitor, the original display settings are restored to your primary display. In addition, all open files and program windows are moved to the primary display. The next time that you connect the same monitor, the Windows operating system automatically applies the display settings that you used the last time that you connected this monitor.

Troubleshooting: Normally, the process of setting up and using a second monitor is seamless and automatic. However, because it involves hardware and software from multiple sources, you may need to troubleshoot problems and make adjustments. For example, if your computer fails to detect the second monitor, first make sure it’s plugged in and turned on, and then, in the display settings, click Detect. Or your computer might not support multiple displays. Visit Microsoft Update, click Custom, and install any available hardware updates. You may also need to visit your computer manufacturer’s website to install an updated display driver. Or you may need to install an additional display adapter.

You’ll find that having two monitors can forever change the way you work with your computer. Be creative and experiment with the sizing of application windows and what information you can keep in constant view while doing multiple tasks.