I'm sorry to hear that you're having this issue.
It could have been an issue with how it's shipped all the way to a voltage spike in the electrical supply. The variables to determine what would have gone wrong in any one instance would be almost impossible to determine without being able to open up the unit and inspect it.
Usually the guys at your retailer are pretty good about helping out. If you end up requiring service, I'll be happy to point you in the right direction. Again, I'm sorry this happened to you out of the gate, so to speak.
I bought my UN55C8000 just under 2 weeks ago, As of yesterday mid-day everything was great with it until, the screen started displaying colored vertical lines(think psychedelic colors)with audio from whatever channel might be on. When I try to use the remote I cannot even see any of the menu screens. I have the TV hooked up to a Comcast Motorola HD DVR using Rocketfish Ultra High Speed HDMI cables.
I called Tech Support and the woman recommended that I fill out an online service request form after she couldn't determine the problem.
I'm gonna return it to Best Buy for a brand new one, but I think that this should not be happening with this new and expensive of a TV!
Anyone have any ideas as to what might have caused this?