Le40m86bdx picture not sharp

I have a two and a half month old Sharp, LC-19SK24U-W. It was fantastic with fantasic, clear, beautifully colored picture until two weeks ago. All of a sudden, the picture starting getting darker and darker. Nothing had been adjusted from day one when I set up contrast, etc. This comes and goes but most of the time is an issue. I can make it a bit lighter but then it is so fuzzy and grainy it is a very poor picture. Also, while this began, one time the television turned itself off and then back on without a power surger or anything.

HELP!