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[nextpage title=”Introduction”]
With the prices of LCD monitors falling every day even regular users may be thinking of installing a second video monitor to their computer. With two displays you not only gain a bigger desktop, but you increase your productivity, as you can have two programs maximized to full screen at the same time (e.g., an Excel spreadsheet on one display and a Word document on the other display) and you won’t waste time minimizing and maximizing windows to read and copy information as it occurs on a typical working environment with just a single video monitor. After working with two monitors it is hard to go back to a single display system! In this tutorial we will teach you how to check if your computer can accept a second monitor without any extra hardware parts, how to physically install a second monitor to your PC and all Windows configuration that may be needed. Read on.
The first thing you need to check is whether your PC accepts a second video monitor or not. To learn that all you need to do is to look at the rear panel of your computer. Follow the cable that connects your video monitor to your PC and you will find the rear end of your video card.
Nowadays all video cards have two video outputs, allowing you to connect directly two video monitors to your PC without any extra hardware part. However, if you computer has on-board video – i.e., your computer doesn’t have a real video card; the video is produced by the motherboard – you may have only one video monitor installed on your PC. This feature is also known by other names like integrated video or integrated graphics. If this is your case, you will need to buy a “real” video card to install on your PC, making sure that your motherboard has an available slot for installing an add-on video card (some very low-end motherboards with on-board video don’t have a slot for video card available, making it impossible for you to have two video monitors on your computer).
Great, but how can you tell what kind of configuration your PC has? That is what we are going to teach you.
On Figures 1 and 2 you can see the rear end of the two most popular kind of video cards you can find on the market. Follow the cable that connects your video monitor to your PC to see what kind of connectors you have available on your PC. The video card shown in Figure 1 has two DVI connectors, which have several pins and is usually white in color, while the video card shown in Figure 2 has one DVI connector and one VGA connector, which has 15 pins and is usually blue in color.

Figure 1: Video card with two DVI connectors.

Figure 2: Video card with one DVI connector and one VGA connector.

Since you probably have already one video monitor installed to your PC, what you will typically see when following the cable that connects your current monitor to your PC it what is shown in Figure 3: a DVI connector is available. This is where you will connect your second video monitor.

Figure 3: Usually a DVI connector is available on a typical PC.

If you can’t find a VGA or DVI connector available or if it is located on a different position from the one shown in Figure 3, this probably means that your computer has on-board video. On next page we explain this scenario.
[nextpage title=”Dealing With On-Board Video”]
If your PC has on-board video, you need to carefully check whether it has a second video output or not. The majority of PCs with integrated video do not support two video monitors without the installation of a “real” video card, but if you are lucky enough your PC will have a second video output.
In Figure 4, you can see the rear panel of a typical motherboard with on-board video. As you can see, there is only one video connector (a VGA connector), which is probably already being used by your current video monitor. If your computer is like this then you cannot add a second video monitor directly: you will need to buy an add-on video card. We will talk more about this below.

Figure 4: Typical motherboard with on-board video. This motherboard (an ECS GeForce6100SM-M) has only one video output.

If you computer is like this one you will need to buy a video card and install it on your computer. With a “real” video card installed you will be able to have up to three video monitors connected to your PC (one on the on-board VGA connector and two to the new video card you will install) – you need to buy a video card that has two video outputs, of course. Please notice that very low-end motherboards don’t have a slot for installing an add-on video card. On current computers this slot is called “x16 PCI Express slot” and you should check whether your computer has this kind of slot or not by taking a look at the motherboard manual or by physically looking for this slot directly on the motherboard. In Figure 5 we show the same motherboard from Figure 4 pointing out the location of the x16 PCI Express slot. Please note that the color of the slot is irrelevant: you can find it in black, blue, yellow, orange, red, etc.

Figure 5: The x16 PCI Express slot.

In Figure 6, you can see the rear panel of a motherboard with on-board video that has two video outputs. With this motherboard you can install a second video monitor without any extra hardware part. Since your current video monitor will probably be connected to the motherboard VGA connector, you will have the same scenario portrayed in Figure 3, i.e., all you need to do is install your new video monitor to the available DVI connector.

Figure 6: Motherboard with on-board video and two video outputs (ASUS M2A-VM).

[nextpage title=”Connecting The Second Video Monitor”]
Connecting the second video monitor is pretty straight-forward, however there are a few things you need to know before going further.
All the steps described below must be performed with your computer turned off.
We are assuming that the video connector available on your computer is a DVI connector. Video monitors, however, can come with a VGA connector, with a DVI connector or with both. Of course your best option is to buy a video monitor that has a DVI connector.
After buying your second monitor, you need to take a look at the kind of connector it uses. In Figure 7 show how the VGA and the DVI connectors look like, however you should take a look at the rear of your monitor to see what kind of connection your video monitor has. Several monitors nowadays come with both connections (see Figure 8). If you have a video monitor like this you should use only the DVI cable and not use the VGA cable that comes with the product.

Figure 7: VGA vs. DVI connectors

Figure 8: This video monitor (Samsung SyncMaster 932BW) has both VGA and DVI connectors. Use the DVI one.

If your video monitor doesn’t have a DVI connector, you will need to use an adapter to convert its VGA connector into a DVI one (see Figures 9 and 10). This adapter comes with the video card.

Figure 9: Two VGA-to-DVI adapters (you will need only one, of course).

Figure 10: VGA cable converted into to DVI.

[nextpage title=”Connecting The Second Video Monitor (Cont’d)”]
Now all you need to do is to connect the video monitor cable to the DVI connector available on the rear of your computer, as shown in Figure 11. Notice that there is only one position that the plug present on the monitor cable will fit the connector available on the video card. So if they are not matching don’t try forcing the plug; simply rotate it 180°.

Figure 11: Installing a second video monitor to your PC.

After fitting the video monitor plug on the video card connector, rotate clockwise the two thumbscrews available, see Figure 12.

Figure 12: Rotate the two thumbscrews available.

In Figure 13, you can see the cables from the two video monitors correctly installed.

Figure 13: Second video monitor correctly installed.

Now that the two video monitors are installed, you need to turn on your computer. Windows will automatically detect the second monitor and will expand the desktop to it.
Some extra configuration may be necessary. Even if the two video monitors are working fine we recommend you to follow the steps shown in the next page in order to make sure that your monitors are configured for the best video quality.
[nextpage title=”Configuring Windows”]
Two basic things need to be done in Windows: to configure your video settings and to install the video monitor driver.
First you need to check if the video monitor driver is installed. Right click on your desktop choosing “Properties” (or “Personalize” on Windows Vista) from the menu that will show up. Then on the window that will pop up, click on the Settings tab (on Windows Vista click on Display Settings). On this tab click on the drop-down box under “Display” to see if both video monitors are being correctly detected. Windows must show the manufacturer and model name for each video monitor you have (see Figure 15). If this is not happening – i.e., Windows is listing your video monitor as “Plug and Play Monitor,” see Figure 14 – you need to install the monitor driver, which is available on the monitor CD-ROM. Insert the monitor CD-ROM on your optical drive and install the video monitor as instructed, then repeat the above procedure to make sure that the video monitors are being correctly recognized.

Figure 14: The driver for the video monitors isn’t installed.

Figure 15: Video monitor with their drivers correctly installed.

On the same window you need to configure the video resolution for each monitor. If you are using LCD monitors, you must configure them with the maximum resolution possible (1440×900 on the video monitors we were using). LCD monitors only present their best quality when they are configured to run under their native resolution, which is usually the maximum resolution supported by the monitor. If you configure them with a lower resolution you will notice that the image will be a little bit blurred. After configuring the resolution for one monitor click on Apply and then select the other monitor on the “Display” drop-down box and repeat the process.
After configuring the resolution you need to configure the refresh rate for each monitor. On the same window click on Advanced button (“Advanced Settings” on Windows Vista) and then, on the window that will show up, click on Monitor tab. There select the maximum value possible under “Screen refresh rate” and then click on “Ok,” see Figure 16. Repeat this process for the second monitor, i.e., select the other monitor on the drop-down box present in Figure 15 and then repeat the process.

Figure 16: Configuring the refresh rate.

There are other configurations that can be done using the video driver control panel, i.e., the control panel provided by NVIDIA or ATI. Under this control panel you can configure, for example, if you want a big desktop or that the second monitor repeats the same image that is being displayed on the first monitor. You can also configure if you want your displays side-by-side (i.e., one at the left and the other on the right) or if you want them to be configured as one on top and the other at the bottom. The amount of extra configurations present on the video driver control panel depends on the manufacturer (NVIDIA or ATI) and even on the driver version, so we won’t be covering these options on this tutorial. However we advise you to explore the video driver control panel at least for you to have an idea on the extra options you have available. The video driver control panel is usually accessed by an option added by right clicking the desktop and/or through a small icon located at the system tray (i.e., besides the Windows clock).