In order to rule out an AV issue, please remove all cabels (HDMI, SCART, optical and coax) cables from the device, just leaving the power cable attached. Then unplug it from the wall await 5 minutes plug it back in and see if it turns back on.
If the fault persists its likely the fault is to do with the main board which has failed, and will need to be replaced.
Should you want me to recommend a repair centre to replace the board, please provide your postcode.
The fact the TV is only a couple years old I think it would be worth repair, I would recommend Colin at Fairfield TV's, he charges £20 to come to you and look at the set, but is a electrical engineer so will replace faulty components (where possible) rather than replacing entire modules, which often makes the cost of repair worthwhile. His number is(###) ###-####0454, and has availability this week to come and see you.