Power light is on, but screen stays black

Drywall couldnt make a set stop working or I wouldent have a working set in my house, as I have been doing construction on my houise for 4 years now and yes theres alot of dust in my sets but they aLL work; The only thing I can think off that it may have knocked something loose or the set was wready to go and it was pure coinsidence that bthe set went out. if your not a tech please take the set into ma repair shop as these sets have no user serviceable parts inside and will cause death if not done properly. Good Luck