Did this on a Windows XP x64...
Step by step guide to switch the monitor to the center:
1. You need to have the new firmware 6.56
a. go here: http://www.matrox.com/graphics/en/support/drivers/
b. choose product and OS
c. load the Software Suit 2.05.00.020
d. load the Firmware utility t6.56
2. Install the Software Suit and run the Wizard to a Single Screen resolution native to your displays.
3. Start the Firmware Utility with the Matrox connected to a USBport directly in your PC
a. make a backup of your current firmware!!
b. restart the firmware utility!
c. update your firmware using the tool. It should point directly to the .pgk-file you need.
4. Start the Matrox PowerDesk
a. go to Multi-Display Setup and then open the GMX dropdown menue!
Menue should look like this:
b. press "Swap Displays" once.
c. the screen is now in the center display. there is a test splash screen over it all white... just click it!
d. save a profile as "SingleScreen"
e. end Matrox PowerDesktop
5. run the Wizard from the start menue and set to a triple screen setup with three times native to your display.
finished...