Shuttle FN41 problem

Hi.

I have a Shuttle FN41 and can't figure out why No.1 VGA port won't show greens and reds, yet VGA port No.2 shows all colours beautifully. I have just purchased another monitor so I can have two running at once, and the problem still exists. They are both CRT monitors. I have tried updating my nVIDEA driver with no luck. It doesn't matter which monitor goes in which VGA port, No.1 port won't display all colours. Does anyone have a clue why this is happening.

Thanks.