Samsung LE40R73BD LCD TV?

HI, I've had my Samsung TV for over 3 years now. The problem started last week; just for information we have Sky HD connected to the tv as well. The problem is we can be watching tv when suddenly we will lose the picture (or the picture will freeze) but we still have sound. The problem is sporadic and can happen a couple of times a day and last for an hour at a time or not at all.

As the tv is over 3 years old it is obviously out of warranty. What else can we do other then buy an new tv which is not an option at the moment. If anyone can help i would be most grateful.