Ok....the FIRST thing you should do is this.
Unplug your TV's power cord from the wall and give it 5 minutes so the TV's computer RESETS.
You could simply have a locked up micro.
Plug it back in. see if the TV turns on, or at least the light on the front of the TV lights up.
If it does light up, and if you can turn it on and off....your micro is ok.
If you turn the TV on....and the TV turns itself off, and blinks....count the blinks between the 3 second pauses.
That isolates your problem.
Then I can look at what is happening to your TV set, and give you an estimate of repair.
I just hope your TV just needs the 5 minute unplug to get it started again.