Tv has died
When the TV is on, if you look at the screen and can see dark images, then you will need to replace both the inverters. The inverters drive/power the back light inside the LCD to show the images. You may have to try and different channels and or inputs to truly see if you can see dark images while the TV is on. If you are hearing audio from a channel or an input then you should be able to see the dark images if just the inverters are bad.
If the screen is dead black without any dark images, then typically your LCD screen/module is bad.
If the TV powers up (power supply is good), you have audio and the remote will work with the TV (the main board is good), the only parts left is the inverters or the LCD screen/module.
I can get you LG part numbers if you need them.