Windows XP might be known as an operating system with a (dual) view. Windows 2000 initially introduced multi-monitor support, delighting multitasking individuals by allowing us to spread our desktops across as many additional screens as we had video cards (up to nine secondary monitors, for a total of 10 screens). Windows XP has improved on multi-monitor support, making it easier to set up and configure and support Dualview on laptop computers with two-port video cards (allowing you to run two monitors off the same card). In this Daily Drill Down, I’ll tell you how you can easily increase your screen “real estate holdings” with XP.

The XP difference
More room onscreen is like money; no matter how much you have, you always seem to need a little more. As our operating systems become more powerful, we tend to do additional multitasking. It’s not unusual for me to have a dozen or more programs and documents open at a time.

For a while, I kept buying bigger monitors, but after hitting the 21-inch point, that strategy got too expensive. The logical step was to spread the desktop across more than one monitor. (I had plenty of extras sitting around, after all that upgrading.) In Windows NT 4.0, though, that was more easily said than done. The simplest solution was a multiple-head video card, but those were close to a thousand dollars. There had to be a better way. And when Microsoft released Windows 2000, there was.

Getting there could be frustrating, however, if you didn’t have the right secondary video card(s). When I set up multiple monitors in Windows 2000 for the first time, with an ATI Rage Fury as my primary card and two inexpensive Diamond Stealths as secondary cards, I went through hours of grief before the secondary adapters were recognized. With XP on the same machine, multi-monitor setup was truly Plug and Play. See Figure A for a photo of my multiple-monitor arrangement.

Figure A
A multiple-monitor arrangement allows you to spread windows across screens.


The first betas of Windows XP Home Edition did not support multiple monitors; this feature was only available in XP Professional (and the server products). Microsoft added multiple-monitor support to XP Home Edition in RC1.

Let’s look at the process of installing multiple monitors on an XP Professional computer.

Installing and configuring multiple monitors
The first step is selecting the hardware. For multiple monitors using multiple video cards, you can use AGP or PCI cards or a combination of the two. If you have a motherboard with onboard video, you can use that for the primary monitor and add-on cards for the secondary monitors. You can check the XP Hardware Compatibility List (HCL) on the Microsoft Web site or the list of XP compatible hardware in the Help and Support Center.


It is possible to use a television set as a secondary monitor if you have a video card with a TV-out port, such as some models of the ATI Rage Fury. Image quality is inferior to that of a monitor, but this may be useful for playing DVD movies or games.

The onboard video adapter should be set as the VGA if you want to use it as part of your multi-monitor setup. Your system BIOS may allow you to choose which adapter will function as the VGA device. The monitor connected to the VGA device is the one that will display the POST and startup information prior to loading of the operating system.


By default, the PCI slots are listed in the BIOS before the AGP slots; this means that if you combine PCI and AGP cards, a PCI card will generally be set by the computer as the VGA adapter. If you have a PCI card that allows you to disable VGA with a jumper setting, you can use the AGP card as the VGA device, even if the BIOS doesn’t allow you to change the enumeration order.

One monitor will be recognized by the operating system as the primary monitor. This is the monitor on which your Windows XP logon screen and taskbar will appear.


The adapter set as the VGA device and the adapter for the operating system’s primary monitor do not have to be the same.

Plug and Play detection and installation
After you install the secondary adapter(s), Plug and Play should detect them when you restart the computer. The drivers will be installed automatically. Although this was not always the case in Windows 2000, I have installed secondary video cards on several XP machines and have found the detection and installation of appropriate drivers to work flawlessly.

It is, however, important to note that the adapters must support the ability to function as secondary adapters (that is, you must be able to disable VGA on the secondary adapters). This can be done via the software or, in some cases, by changing a jumper setting on the video card. If you have a card that does not support this, it can still be used as the VGA adapter.

You can check to see that the drivers are properly installed by right-clicking My Computer | Manage and selecting Device Manager under System Tools in the left console pane. Expand the Display Adapters node in the right details pane and ensure that there are no error icons (red Xs or yellow question marks). See Figure B.

Figure B
Once installed, the display adapters appear in Device Manager.

Configuring the Display Properties to use multiple monitors
Okay, you’ve installed the secondary video cards, plugged in the monitors, installed the drivers, and the devices are shown to be working in Device Manager. You turn on the secondary monitors and…nothing.

That’s because you have to tell Windows XP that you want to extend your desktop across the secondary monitors. Open the Display applet in Control Panel (or right-click the Desktop and select Properties from the context menu) and then click the Settings tab, as shown in Figure C.

Figure C
Monitors for the installed adapters will appear on the Settings sheet.

All monitors should show up here, numbered according to the following scheme:

  • The primary monitor is labeled number 1.
  • The secondary monitors will be numbered 2 through 10, according to the slot occupied by the video card of each.

By default, the primary monitor is selected and its properties are displayed. To extend the desktop to a secondary monitor, click the numbered box representing it. This will cause the properties for that monitor to be displayed, as shown in Figure D.

Figure D
Select the check box, as shown, to extend the Windows desktop to this monitor.

To extend the Windows desktop to the selected secondary monitor, check the Extend My Windows Desktop Onto This Monitor check box. Click Apply, and your Windows background or wallpaper should appear on the secondary monitor. Repeat the process for each secondary monitor.


By default, all icons and toolbars will appear on the primary monitor, and all applications windows will open there. You can drag any of these screen elements to another monitor.

You can change the settings (resolution, color depth) independently for each monitor. You can also select which monitor you want to function as the primary monitor.


Note that you can connect to a multi-monitor system with Windows XP’s Remote Desktop Connection (RDC) service. (You must enable support for remote connections in the System applet in Control Panel, using the Remote tab.) RDC is a new and improved terminal services client and, unlike Windows 2000, XP allows you to use it to connect to XP Pro machines as well as servers. Only the primary monitor’s screen will display in the terminal window.

Identifying the monitors
You may not know which AGP/PCI slot corresponds to each monitor. To determine which monitor is which, click the Identify button. This will cause large numbers to appear on each screen, matching the numbers in the Settings box.

If the left-to-right arrangement (or up-and-down, if you have monitors stacked above one another) on the screen doesn’t match the physical arrangement of your monitors, you can drag the screen monitors to the correct positions.

The positions of the monitor icons on the Settings sheet are important because they govern how items are dragged from one screen to the next. If you find that you can’t drag an item to the left onto a monitor that is located to the left, it may be due to the fact that the monitor icons are out of place.

Setting up Dualview on a laptop or notebook computer
Dualview is supported on mobile computers and some display adapters on desktop machines that have two video ports. With Dualview, you can spread the desktop across two monitors without installing more video cards.

To use Dualview with a mobile computer, just plug a monitor into its Video Out port. Start the computer, and Windows XP will automatically detect that the second monitor is present.

As with multiple adapters, you still must configure the display settings to extend the desktop across the second monitor. The mobile computer’s LCD display will always be the primary monitor, with the external monitor functioning as the secondary. With Dualview, you cannot select which monitor will act as primary.


You can also add multiple monitors to a laptop or notebook by using PCMCIA (PC Card) video adapters for secondary monitors.

Troubleshooting multiple monitors
If you have followed these instructions and your Windows desktop is not displaying across all your monitors, there are several factors you should consider.

Common causes of multiple-monitor problems
If you have multiple-monitor problems, you should first look into these common issues:

  • Ensure that your video cards are the AGP or PCI bus type (ISA is not supported) and are on the HCL.
  • Ensure that all adapters are shown in Device Manager, with no error icons or conflicting devices shown.
  • Ensure that your secondary monitor(s) is enabled on the Display Settings sheet.
  • Check to see whether you need to update your video drivers to act in the secondary role.
  • Adobe Type Manager is incompatible with the Windows XP multiple-monitor feature. You will have to remove Type Manager to use multiple monitors.
  • If you have an older computer, the BIOS may not support Windows XP display features. You may need to upgrade the BIOS. (Contact the motherboard vendor to find out if a BIOS update is available.)

If you have selected display settings that are not supported by your video card or monitor, you may need to restart Windows XP in Safe Mode to change the settings. Safe Mode loads Windows with basic VGA drivers in low resolution (640×480).

Multiple-monitor limitations
Note that there are some limitations to the multiple-monitor feature. For example, you cannot run full-screen MS-DOS applications on a secondary monitor. Also, you cannot drag a maximized window to another monitor.

Many games are not able to run full-screen on secondary monitors; however, there are some games, such as Microsoft Flight Simulator, that can. Some games that support multiple-monitor displays with dual-head video cards, such as the Matrox G400, do not support multi-monitor displays using other cards.

Troubleshooter tool
Windows XP Professional includes a Video Display Troubleshooter tool, which includes a section on multi-monitor problems. Access the tool by clicking the Troubleshoot button on the Display Properties’ Settings tab (see Figure E).

Figure E
The Windows XP Help And Support Center includes a Video Display Troubleshooter.

Color calibration
If you do graphic design work, photo manipulation, or other applications that require your multiple monitors to display colors identically, you will need to calibrate the brightness, contrast, and color temperature of each monitor to make sure they match.

You may be able to adjust the settings of each monitor to your satisfaction by either using the monitors’ controls or using the display driver calibration controls (accessed via the Advanced button on the Display Properties’ Settings tab). If you need more precise calibration, there are third-party programs available, such as PowerStrip.

Multiple-monitor support is an especially handy feature, and Windows XP Professional has improved on the multiple-monitor support introduced in Windows 2000. Setup and configuration of multiple monitors is quick and simple, and the Video Display Troubleshooter addresses most common problems.

In this Daily Drill Down, I have discussed how to install and use multiple monitors in Windows XP and what to do if you encounter problems along the way. For more information on multiple-monitor use, including how to use multiple monitors in other operating systems such as Linux, there is an excellent resource at Realtime soft.