Screen background color turned pink

Power OFF the monitor before doing this. You don't have to power off the computer.

Your video cable is loose. Most likely on the back of your computer. Push cable in tight and tighten the thumb screws.

Turn ON the monitor

If this doesn't work, then (seriously) *whack* the monitor on the left or right side with the palm of your hand. If this corrects the problem it is temporary (you will need to replace the monitor or have to deal with a sore hand).

Hope this helps!