Surprisingly, the upgrade is a simple one and natively supported by Windows XP, 2000, ME and 98. Setting up multiple monitors is a simple enough process that even a novice can handle it without difficulty. The only essential hardware required is an additional graphics adaptor.
You can either replace the current graphics adaptor with a dual head card or add another separately. If you are building from the ground up, the easiest way to connect two displays is by using a dual-head graphics adaptor, such as nVidia's GeForce 6600 PCIe card. Follow the manufacturer's instructions on installing the graphics adapter.
With your hardware properly installed, setting up your dual monitor system is simple. In 'Display Properties' in Windows, navigate to the 'Settings' tab, and you will see controls for both monitors.
The two monitors can be enabled, disabled, resized and reoriented to your requirements. Select 'Extend my Windows desktop onto this monitor' to allow your cursor to navigate across both screens.