Windows 98 (from the Display.txt file in Windows):
Determine which card you want to use as your primary card. First make sure that the card works with multiple monitors. If you are using an AGP and a PCI card, check in the BIOS for the option to set which will be initialized first. The first initialized will be your primary card.
Insert the card into your motherboard, and then add your second card. The system BIOS will decide which card is the primary card. One way to verify which card is your primary card is to check which card displays the Windows 98 Startup logo when you turn on the computer. The card that displays the Startup logo is the primary card, and the card that appears to be inactive is the secondary card. If this is not what you want, reverse the order of the cards in the PCI slots.
Repeat this procedure for each additional card. Unfortunately, with current system BIOS’, there is no way to determine which adapter will be the second, third, or fourth card until the card is actually used (exception being PCI/AGP combinations).
Start Windows 98 Second Edition. Windows automatically detects the new cards. When you are prompted, restart your computer.
During Startup, Windows initializes the new secondary adapter and displays a message indicating the card is correctly initialized.
If the primary card displays in 640×480 and 16 colors, right-click the desktop, click Settings, click the Colors down arrow, and then select the 256 Colors setting or a higher setting. Click OK, and then restart your computer.
After you log on, right-click desktop, click Properties, and then click Settings. In the Display area, Windows lists each video adapter in your system. Find the adapter you want to use, and click it.
Click the Extend my window desktop onto this monitor check box, and then click Apply.
You can now adjust each monitor separately, including refresh rate, resolution, color depth and relationship to each other in Display Properties/Settings.
If you are using the Matrox G400 Dualhead, it is even easier since you only install one card. In Windows 98, the secondary monitor can be controlled exactly like two monitors are, with the additional options of having the monitors mirror each other, having one provide a zoomed image, or other effects provided by the Matrox powerdesk.
Windows 2000 (from the Windows 2000 Help file)
To install additional monitors
Turn off your computer.
Insert your additional Peripheral Component Interconnect (PCI) or Accelerated Graphics Port (AGP) video adapter into an available slot.
Plug your additional monitor into the card.
Turn on your computer. Windows 2000 will detect the new video adapter and install the appropriate drivers.
Open Display in Control Panel.
On the Settings tab, click the monitor icon that represents the monitor you want to use in addition to your primary monitor.
Select the Extend my Windows desktop onto this monitor check box, and then click Apply or OK.