My computer has a Soltek SL86SPE2-l) motherboard with an Nvidia Geforce 7600 GS running Windows XP. The computer has two monitors connected to the video card, but when attempting to active the dual monitor view I cannot see the second monitor in the display settings. This occurs in both the Windows Display control panel and the Nvidia Graphics utility. Downloading and install the latest drivers from Nvidia does not resolve the problem. How can I activate the second monitor connected to the computer?

The Nvidia Geforce 7600 GS video card installed in your computer should allow two monitors to be displayed at the same time (through extending your desktop onto the second monitor) so therefore something seems to be wrong with your setup or configuration. The reason I raise this point is that while some video cards have twin monitor outputs on the card (e.g. a VGA output and DVI output) they can only send video to one of those outputs at a time, meaning you cannot use both monitors simultaneously or extend your desktop onto the secondary monitor. However, since your Geforce 7600 GS should support the dual monitor function we need to investigate further as to why this is not working.

The most common problems with dual display on a video card are when both monitors can be seen by the computer in the Display control panel (or the Nvidia control panel) but the user can only select to output to one monitor at a time or clone the displays (i.e. display the same output on both monitors, rather than extending the desktop across both monitors). However, in your case the computer does not even recognise the second display, indicating it does not know that the display is present. As a first step, we need to ensure the monitor is connected to the computer properly. Since there are various different brands of graphics cards which use the Nvidia Geforce 7600 GS chipset I will assume that your make of card has two monitor outputs: one being a VGA output, and the other being a DVI output. Disconnect the monitor which is functioning correctly at the moment. For example, if you have a monitor connected via DVI with another connected via VGA, and the DVI monitor is functioning correctly, disconnect the DVI monitor. Once this has been done, restart the computer and check whether the computer displays on the other connected (in our example above, VGA) monitor.

During the power-on self test (i.e. all the computer self-tests which occur before Windows loads) check whether the POST information is displayed on the monitor. The POST is hardware based and completely independent of the Windows installation and, as such, provides a good indicator of whether a problem is related to Windows or not. If nothing appears on the monitor during the POST this indicates that something is wrong with the computer hardware. The most likely suspects are the monitor and graphics card. First, the monitor could be broken and is not working correctly. To test this theory, try connecting the monitor to another computer to check whether it displays properly. If not, you should consider having the monitor fixed (or acquiring a new monitor) since this one seems not to work. However, if the monitor displays correctly then the second reason for the lack of display is something wrong with the video card in the computer. It is possible the output on the video card is not working correctly. There is not much you can do to test this theory, but in this case it would be a good assumption that something is wrong with the video card. Therefore, you may wish to seek a replacement card under warranty (if available) or replace the video card outright.

In the case that the monitor displays correctly during the POST, but does not display after Windows loads, this strongly indicates that something is wrong with Windows interfacing with the video card. That said, it is quite strange that the monitor will not display since this is the only video output device available. As a first step, shutdown the computer and reconnect the working monitor to the computer. As you are unable to see anything on the screen, you may need to press the Power button on the computer to trigger a controlled shutdown, or forcefully power-off the computer (as a last resort). After reconnecting the good monitor, boot the computer into Windows, where we can commence troubleshooting this issue. You have already tried installing the latest Nvidia drivers for the graphics card, without fixing the problem, so we can rule out that possibility. However, if more recent drivers have been released since you last attempted the reinstallation then I suggest you try downloading and installing these latest drivers (just in case). Assuming that Windows still does not recognise the presence of the second monitor, and will also not display from that monitor when the computer only has that monitor attached, you should next try running the Windows System File Checker. This utility will check for any missing or corrupt Windows system files, which may perhaps be causing problems with the graphics card. Go to the “Start” menu > “Run” and type ?sfc /scannow? (without the quotes) and click OK. Make sure you put a space between the “sfc” and “/scannow” portions of the command. The System File Checker will launch and commence operations. Once it has finished scanning the computer, and correcting any detected errors, the SFC utility will exit silently with no user feedback. At this time you can restart the computer, and check whether the problem persists.

Should the problem still continue, you may need to complete a repair installation of Windows XP. This will not scan for any corrupt files (which is what the System File Checker does) but will instead replace all system files on the computer, leaving your personal data file intact. However, this should only be completed if you are confident about this process. Additionally, you must have a backup of all your data before commencing this process. While the repair installation should not affect your personal data, things can always go wrong which may result in your personal data being lost. Therefore, you must have at least one backup (or preferably, multiple backups) of your data before continuing. Once you have a backup of your data, insert the Windows CD into your CD drive and restart the computer. The computer should restart into the Windows Setup. At the Welcome screen, press ENTER to “Setup Windows XP now”. DO NOT press R to “Repair a Windows XP installation”. Despite the name of this option, this is something completely different which we do not want. At the next screen, accept the licence agreement. Your existing Windows XP installations should now be detected. Select your existing Windows XP installation and press R to commence a repair. The Windows setup will commence copying files to your computer. Once this has finished, the computer will reboot. On this reboot you may see a message saying “Press any key to boot from CD”. Do not press a key to trigger the setup ? the computer will automatically boot itself into the Windows setup, where the repair installation will continue.

Dealing with the final scenario, if the computer recognises the second monitor in both POST and through Windows, this indicates that the hardware is fine and that Windows can correctly recognise and interface with the monitor output. However, it seems that Windows is unable to use both outputs at the same time, and refuses to even acknowledge there is a second output with two monitors connected. In this case, verify that your graphics card does indeed support multiple monitors. This should be detailed in the graphics card manual, or alternatively visit the manufacturer’s website for details about this aspect. Assuming your graphics card does support multiple monitors then please contact me for further advice on this unusual scenario.