Entertainment Center: TVs, Stereos, VCRs and DVDs - Weird Functioning

I have a 27inch Sharp TV.It functions weirdly.Most of the times(7 out of 10 times) when we switch on neither picture nor sound functions.If picture(2 out of 10 times) and sound functions on it stops automatically after 5-6 mins.Hardly one out of ten times it functions normally.This has been happening from a month.Earlier it was working normally.
So please help me out what could be the problem and the cost involved in repairing it.

Most of the time (7 out of 10) I will answer your question. But 2 out of 10 times it will be the wrong answer but out of those 2 times i give 1 answer and 10 times it could be right. Then again if I answer 10 questions I might be right 5 times if they where good questions but most of the time 7 out of 10.
To answer this question it might be the time when 2 out 10 times I'm right.

What where your symptons again? WEIRD is not a good word to describe something if you want specfic info. My uncle is weird but only to me as he puts his hair on upside down.

Sounds like you have bad connections on the circuit board or possibly a failing voltage regulator.

Thanks for the reply..When i mean weird we are not sure when we get the picture and sound.
Sometimes we get them and sometimes we do not.2 out of 10 times the sound and picture comes...
Symptoms: Sometimes the TV starts normally and we can see the picture and hear sound.
Most of the times neither Picture nor sound comes and TVswitches off with a small pop sound.