Sharp 1650 Computer out input B&W problem

Sharp 1650 Computer out input B&W problem

I have this weird problem.

When i connect my DVD player to the panel using s-video or rca inputs, its great, i get color and good picture.

But when i connect my computer to the panel using video out of the video card to rca or s-video, i get black and white.

The same video out works great(color and picture) when i connect it to my TV.

The knob is rightly set at NTSC, so thats not it.

Its driving me crazy, help me someone, please.

Thanks in advance.