My 42 in LCD tv, which is about 5 years old went blank. Does anyone know the reason and is it repairable?

Question

I never had the speakers hooked up because i was using a home theater system. It just went dark while i was watching it. And now when i turn it on it goes into stand by mode automatically with no picture at all

Answer 1

Does the TV still seem to work, just no picture?  Like, can you still hear audio when the TV is set to a particular channel?

If so, then probably the light bulb used to light the screen burned out.  Check your manual for ordering a replacement.  This is something you can do yourself, although you need to be careful not to touch the bulb with your hand (it's much like replacing a halogen bulb in one of those lamps.)