Hello, sorry to hear you are having this problem. Since the power reset didn't solve your problem, unfortunately your Tv has a failure and needs parts inside replaced. There is absolutely no way to guess what is wrong, it must be opened up and diagnosed using skill and tools.
I am a technician and can help you save money if you want to try and open the Tv, diagnose, find/order/install parts yourself. Even though I am here to help you, diagnosing your Tv failure is tricky. Working on the Tv all depends on your ability to follow instructions carefully, provide detailed replies/information, use tools to take apart the Tv and replace parts, test live circuits with a meter and use a soldering tool. This takes time and patience and because of the circumstances there is no guarantee of the outcome. If you do want to pursue a DIY repair then you need to have the back off the Tv and then reply here.
If you cannot perform these kind of tests/repairs then you can expect to pay a repair shop anywhere from $250-$350 to fix your Tv. To find a trusted local repair shop just enter your information here:Find local repair shops
Sorry for the bad news. If you want more details then REPLY here (you can reply without rating) otherwise please take a moment to leave a 3-5 rating. You should NOT base your rating on the functionality/failure of your Tv or how this website works. Giving a 3-5 rating now does NOT close the question or prevent you from replying to me and you can come back for a refund anytime (1-2 rating does NOT trigger a refund request).
I will be happy to continue further and do everything I can to provide you with the service you seek. All you have to do is reply.