EMERSON EWL2005 20" LCD

Picture went white after young grandsons had visited. Sound is fine. I wonder if the boys got into the menu and increased the brightness to the max? If so, I can't figure out how to adjust it downward without being able to see the menu on the screen. Our Emerson EWL29S5 20 in. television went white then slowly some color would come into the picture. The picture was split horizontally. The color would swirl across the screen with the picture moving extremely slow. The first few days after about 1/2 hour the picture became normal. Now it does not normalize at all.