Hitachi LCD ultravision green streaks

 My 42 inch hitachi Ultravision LCD tv has developed green streaks on the picture noticible with light background. I read a forum that dust on the lens may be the problem. I cleaned the lens cover and did a good inspection of the compartment and found no problems. I read that there is a hidden repair menu that can be accessed by a sequence of button pushes. Reset the green something or other. Does anyone have any suggestions. It is a 42V715 hitachi ultravision LCD.