I'm sorry to hear that you're having this issue.
I'm not sure what would be causing this problem. If you continue to experience symptoms, I would recommend having it inspected by a technician.
I wish I could help further, but I can't diagnose this symptom without inspecting the unit.
I have this TV and have been really pleased with it. Starting yesterday after being on for several hours it would periodically go black with no sound for several seconds then the "chime" would play as if it was just turnd on and the picture and sound would come back on. The TV never really shut off because the white light stayed lit and the red light blinked. Also the remote would not work for sound or on/off and the switch on the side of the TV would not shut it off either. I had to unplug it to turn it off.
What is causing this?