I have a Hyundai B90A monitor. About a month ago, a green vertical line appeared spanning the entire screen and has changed colors from green to orange to yellow then finally white. It is in front of everything on my monitor (desktop, work, screensaver, etc). Now another line has appeared - this time blue. What are these due to and how can I get rid of them?

Optional Information:
OS: Windows 2000; Browser: IE

Already Tried:
resetting monitor viewing levels, changing screen saver/wallpaper, turning off monitor.