We have a Sony Bravia KDL-40V3000 flat screen television. About 6 months ago, the screen started displaying white, green and black vertical lines and dots. This continued for a few weeks and then the picture came right again. The problem came back again this week. The entire screen is covered in the white, green and black vertical lines and dots. The picture is very bad and it is hard to make out the image. Occasionally for a short time it is better with only some small white dots showing. Does anyone know what the problem is and how much it will cost to fix? I have attached a photo of the picture.