I have found over the years that Samsung makes extremely good quality products. For example I do not remember any problems with their TVs previously on this forum.
Having said that, Which say that a modern TV should last about five years. If they go wrong during that period, there is a high likelihood that there was a manufacturing defect with it.
If I was you I would get on to Samsung explaining this and ask them to repair the TV for you.
T, February 2009