video problem

Does anyone have a solution for this? I just installed a new video card with TV out for my lcd... The problem is that the onboard video is always the primary output. The only two ways i can think of to solve this problem are to run two identical displays from each video card or to disable the onboard video, neither of which I can figure out how to do. There is no setting in the bios to do this and as far as i can see, no jumper on the motherboard either. If anyone can help me out with this it would be a huge help... thanks.

Nothing in the bios that you can change? ... something like 'Video: Boot PCI First'?

Nothing even remotely close in BIOS... If it helps at all, the board is an old Dell P133.

Disable the display in windows. Go to Control Panel->System->Device Manager. Then select the display you want to remove and hit properties. Look for a check box that says "disable"

Call Dell and ask them how to disable it? There must be a way, there always is.