"Monitor screen yellow," we Googled and quickly came up with the solution to a recent yellowing of our screen image: a loose connection. A fellow sufferer out in cyberspace had queried about.com complaining that "It was not always like this, but it becomes more and more serious, about 90% of the time, some time it switches back to normal color but most of the time I got this antique yellow, it was very tired to watch the screen." The solution, from Werner in the Netherlands:
If your monitor sometimes gives normal color, then that could indicate that your cable (between PC and monitor) or plug is broken.
We jiggled the monitor cable where it plugs into the computer, and that was all it took: Our whites are white, and our brights are bright again!