All computer monitors display an image in roughly the same way. By mixing dots of the three primary colours together at different ratios and intensities, a monitor is able to generate virtually any other colour, building an overall image. A computer sends signals to a monitor telling it exactly what dots are supposed to be lit. If the process is disrupted, such as with a bad cable or connector, the video data will be corrupted. This will cause the monitor to display all colours incorrectly, occasionally giving all of them a particular hue, such as pink.
Reset the monitor's colour settings. Most monitors come with their own internal settings for colour balancing. Look through the monitor's internal menu, often accessed by a menu button on the monitor itself. Check to see if the colour balance has been changed and look for a factory reset button. If the monitor is one with a cathode ray tube, look for an option to manually degauss the screen to clear away any magnetic interference that may be disrupting the colour. The option to manually degauss is located either in the monitor's menu or as a separate button on the monitor itself.
Disconnect the video cable from the computer and the monitor. Inspect the connectors on the cable for bent pins. If a pin is bent or damaged, the monitor is not receiving a good signal. This can add a colour tint to the display. You may be able to repair a bent pin using needle-nose pliers to straighten it. Otherwise the cable must be replaced.
Plug the video cable back in securely to the computer and the monitor and power the computer back on. Gently wiggle the connector at both the monitor and the video card. Look for the screen to flicker or change colours. If it does either, there is a loose wire or short either in the cable or the connector itself.
Switch out the cable with a new one. If the problem persists the issue is most likely in the monitor and the monitor must be repaired or replaced. Confirm the monitor is bad by connecting the computer to a different monitor. If you do not have one available, take the computer to a repair shop and have it tested. If the issue persists on a new monitor, the problem is the video card. If it works on the test monitor, the original monitor is confirmed to be the problem.
Unless the monitor is very large or specialised in some way, it is not cost-effective to have it repaired. When a monitor goes bad the cheapest solution often is to simply replace it.