Getting dual monitors to work correctly seems to be a hit or miss affair. In many cases, it's just a matter adding a second video card and monitor and rebooting the computer. In other cases, you need to do some cyber gymnastics to get things working correctly.
The process is the same no matter which version of Windows you are using. First, be sure that your system is working correctly. Boot into safe mode and verify that you have only one video adapter and monitor showing in the Device Manager. If there are more, but you only have one adapter and monitor, you'll need to remove the extras.
Once you're sure that your video setup is working fine, turn off the system and look inside. Remember that you'll need a video card for each monitor that you plan to run under Windows. That means that your system must have a free expansion slot for each one. You may find that you have problems with IRQ sharing or DMA channels, depending on your motherboard and video card, although many video cards seem relatively intolerant of IRQ and DMA conflicts. Install your video card in the appropriate slot, and then connect the monitor.
Restart your system. If all goes well, your computer will boot the same way that it always has…the second monitor will still be dark. If your system prompts you to login, do it. You may need to install drivers for your second video card, depending upon whether or not Windows has built in drivers or not. Just follow the on-screen instructions.
Once the drivers are installed, check the Device Manager to make sure that the display adapter is properly detected:
Once the drivers are installed, open the Display Properties window. In the settings screen, you should see something like this:
You'll see that a second display is shown. Click on the grayed out display marked as "2". The window will change slightly to look like this:
You can then change the desktop resolution and color depth. Once you've done that, click your mouse on the "Extend my Windows desktop onto this monitor" to enable it. Remember that the resolution, color depth and refresh rates of each monitor adapter combination don't have to be the same. The window should look something like this now:
Click on OK and your second monitor should activate itself as an extension of the first:
You'll find that you can change the relative geometries of the two monitors by moving their respective boxes around in the Settings window.
Please reply to me if that doesnt help!!!