Hi,

First try a power reset.

Turn off the TV and then turn off and disconnect the TV power cord from the power outlet. Then press and hold (or turn on ) the TV's power button (or switch) for 30 seconds and release. Reconnect the power cord to the power outlet and switch on the outlet. Turn on the TV and check if it starts OK.

If that doesn't work, switch off the TV and disconnect the power cord from the power outlet disconnect all the cables from the TV and remove the back cover from the TV.

Check the power board (the one where the power cord connections go to) for domed, leaking or blown capacitors and also for possibly any other burnt out or heat stressed component.

If unsure about a component take close up pictures of the component in question and post back here. Hopefully someone will be able to help you further.

Here is a link that shows how to do that.

Adding images to an existing question