I am using LG monitor. For some reason it has stopped working & displaying Red , Greens & Blues display. Now what i can do? Pl. suggest me some trouble shooting tips. Thanks.

My LG monitor seems to have stopped displaying anything. And displaying only Red , Greens & Blues display. When I reset the computer, the LED changes to show that it is recieving a signal. But the screen itself does not work at all. I have tried a different cable & found the same problem.Then I tried another monitor & it works so I don't think it can be the motherboard or graphics card prblem. The monitor is about 3 years old. Any suggestions of anything that I might be able to do to fix/diagnose it? Thanks..