When your monitor starts to lose its color and turn pink it means it’s usually starting to go bad. Rarely if it’s a CRT monitor you can try the degauss feature and it will clear it up. I have seen it where the connection to the computer is loose or the cable itself is shorting which will cause the same type of effect on the monitor. I would jiggle the connection to see if it changes the image. If you have another computer to try the monitor on I would do that as well to make sure it’s not your video card causing the problem although it’s not likely. Do not try to take apart the monitor itself to fix it because it stores a lot of electricity and you can seriously hurt yourself.