Hi. I'm Steve. I'm sorry to hear about your TV. I will try my best to give you a precise and accurate answer.
Your power supply board may be shot. Possibly bad capacitors but that would require a visual confirmation.
Can you do this do you think? If so, remove the back and we'll take a look.
If you have a meter, that would be helpful.
If not, let me know and I'll try and give you a rough quote based on the most likely failure.
Ok, then assuming that it is the power supply that is at fault, you would be looking at about a $250 repair bill split approx. 50/50 for parts and labor.
I assume that the set is over a year old? If so, give me your zip and I'll try and find someone in your area that can help you.
I'll be here if you need more help. I want you to be 100% satisfied with my answer.
If happy, please remember to 'Accept' and/or give me a positive rating so that I am compensated for my time and effort. If you don't, I won't.
Please bookmark my web page at www.stevetheguru.com so that you can contact me with your future electronic questions.
Thanks very much.
Try these guys: http://screencast.com/t/cbo8mcVxh
I'll be here if you need more help.