In the majority of cases this type of fault points towards a hardware failure on the main PCB.
Before going down the route and looking to get the set taken to a service centre, unplug the TV for a few minutes, hold down Volume UP & Volume Down on the TV itself, then plug it back in after 5 seconds if the lights do not come on press the power button.
Should the red\green lights appears, this is a master fault and there isnt really a great deal you can do other than take it into a service centre, for them to strip it down.
Let me know how you get on, and provide me with your postcode if the red\green lights come back or the TV wont turn back on, and I can suggest an engineer in your area.
Good afternoon, my name is ***** ***** just wanted to follow up to see if you required any further assistance as I havent heard back from you recently?
Good evening, I havent heard from you in a while, do you still require assistance?