Forcing DVI output on an older card

Anyone know how to force an older card like a 6600gt with vga and dvi out to use the dvi plug as it's primary output? The only way I know to get that plug working is to tell it to display on two monitors.

MY 6600gt automatically uses the DVI out if I have the monitor hooked up to it.

In the display properties, on the screen where you see monitor 1 and 2, there should be a check box near the bottom that says "use this display as primary monitor." Click on mkonitor 1 or 2 in the picture whichever one is using the dvi port and then click on the checkbox to make it primary.