My (old) Samsung LN-T4671F is having a problem. On a normal picture where there should be the color black, green vertical bars are being displayed. It happens on all inputs and also when everything is unplugged. So when I am at an input/source that has nothing on, the whole screen winds up being the vertical lines. I have a picture; I plugged my laptop in and just took a picture of the homepage of Youtube. Any ideas what it could be and/or if it's easy-medium hard to replace it? I don't have any experience working on tvs but I can follow instructions.