Be sure to call it in now. If from Costco, take it back and exchange it. It's what they do!
Just bought the LED TV in November and it sounded like it was trying to hook up to a landline modem, then the screen looked like a hundred color bars and went black. It turned off and on several times and then wouldn't come back on. Around midnight, 2 hours later it came back on blasting. Had to unplug it to turn if off. Next day, it came on, did the color bar screen and went black. When it finally came back on it doesn't have a sound.