Why a computer monitor would have a tint of one color
If your computer monitor looks tinted (too blue, green, or red, for example), the following tips and information may help you fix the problem.
Monitor cable is defective
Temporarily disconnect the monitor from the back of the computer and verify that there are no bent, burnt, or broken pins. The picture shows a VGA (video graphics adapter) connector and the VGA connection on a computer. Your computer may have this cable or a DVI (digital visual interface) or HDMI (High-Definition Multimedia Interface) cable.
The monitor has two cables, a power cable and a data cable. Follow the data cable from your monitor to the computer. It's also ok to disconnect this cable while the computer is running.
If the end of the cable looks okay, firmly reconnect it to the back of the computer. If you continue to experience the same issue, continue reading through the other possibilities.
Some monitors may use a cable that also needs to be disconnected from the back of the monitor. If the cable on the monitor is removable, follow the same above steps on the back of the monitor.
Monitor is bad
If the cable is not defective and is firmly connected, the monitor is most likely bad. To help verify if it's a bad monitor, connect another monitor to the computer. If another monitor looks fine, it's a defective monitor and should be repaired or replaced through the monitor manufacturer. If another monitor has the same problem, your computer video card may be defective.
On some older CRT (cathode ray tube) monitors, give it a good slap on the side of the monitor to fix this issue, although usually, it's only temporary.