I purchased a 37 inch Dell TV. in 2006 (W3706MC). It has worked fine and I am very happy with the picture quality. A grey shadow line has shown up that is about 1/2 inch wide and runs across the top of the screen. It also bleeds down into the screen. It is always in the same position and never moves. The shadows are really noticeable on a white or light colored image. Is this a common problem? Is there a fix? Thank you for any help or advice you can give me.