Use canned air to dust out the vents and be sure it's not in some enclosure as heat can build up.
Always call it in so the makers can check on recalls and service bulletins.
I have a Samsung LED less than 3 Years old. Recently it started turning off intermittently after about a half of an hour. It would happen when commercials came on or when we changed channels. We thought it was the converter box so we had TWC change put the box. The tech determined it was the fault of the TV. In checking on the net it sure seems this an inherent problem with the Samsung TVs. Any help available? We are looking to get a 70 inch for our lower level, but will not even consider Samsung if this is what we can expect. We are also looking to buy a summer home in Ft. Collins that we need to furnish.