I've heard of the press method. I didn't mention it because that's a temp fix. I've heard of it working, but usually only for a while. It's not something you can do and have it work "forever".
My friend had a plasma TV that had the red dots on the top left corner of the screen. There was nothing to be done but suffer with it. He bought a new TV finally last year and the whole thing works again. You can check the cable or cable box, but odds are it's the TV.