My Sharp 42" LC42D85U tv 1 month old no picture or sound

1 month old Sharp 42" flatscreen wont come on. No picture or sound. We hooked it up to our DVD player Thurs nite and watched a movie. When we finished we couldnt get the tv to come back on. We unhooked it from the DVD player and ran the cable straight to the tv. Still no tv. It says channel not available. The remote wont change channels either.
We have unplugged it and still no picture.. We havent had any problems with it until this. We have tried hooking it up to our old vcr and it still wont work. Now it wont even work to watch a movie on the DVD player.
Any help would be greatly appreciated.