color buttons

I need aprogram that is independent of other programs and will press a button onscreen when a color appears. The color streams in like a narrow ribbon from the right side of the moniter and moves to the left (it can iniate anywhere from the top of the screen to the bottom of the screen) and press another button when the color is no longer there. Total # of colors is 2. There is only one (permanent location , non moving) to detect the presence of color. The speed that the color will appear and move can vary greatly so quick detection is important. Thanks to all in advance. Please include info as to what language and time necessary for the project.