Although it is possible that your monitor is defect, you should first run a monitor test to see if you just need to adjust some of the settings. Go to this
webpage and just follow the instructions.
The test are done best in full screen mode (F11 in most browsers).
Do you have any sources of magnetic fields next to the monitor (speakers, halogen lights, sometimes even a cordless phone can cause distortion).
If you can, connect this monitor to another computer and see if the problem persists. This way you eliminate any hardware related issues (cable, video card).
If you have any more questions (also regarding the results) come back here and leave a comment. I will check back and see what else we can do.