monitor problem or something else??

I just bought a new 21 inch widescreen lcd, it worked fine for the first 30 days. but a few days ago I turned it on and once I got into windows I noticed to the right of the screen there were a ton of lines. They span about 1 inch, and they are from the top to the bottom of the screen. they react when I move the mouse courser over them by lighting up the width of the mouse cursor across the entire sceen. Sometimes they all just go away for a few mins but come back pretty quickly. I put on old 17 inch crt in its place for a day to see if it would happen and it didnt happen. So I am pretty sure its the screen. Any suggestions?? also sometimes at towards the top of the screen the lines go all the way across the screen. also when I just have a white background I can see small lines that cover the hole screen. But the right hand side it by far the worst.