Other than to give it a BST (British Standard Thwack) in the hope that whatever inside that might have come loose reconnects itself again I personally would begin to dismantle the thing taking care to note how you go so that it can be reassembled once it begins to work again which it is in all probability likely to do unless when it stopped working it did so with accompanying funny smell, blue flash or other such near cataclysmic occurrence.
For your safety, have it disconnected from the mains until such time you�ve identified at at least the �mains-live� parts within. In the olden days of CRT tellies you�d have to keep your eye on the tube as well.
Then, inside the thing, work through each removable and re-seatable circuit-board in turn. It�s quite possible that a loose connection has occurred that was not fixed by the BST suggested earlier.
I have a Fujitsu Plasma that failed just outside the guarantee period and deliberately, I suspected. �Picture went�. However and at the time it was cost-effective to return it to the manufacturer�s local service agent and pay them to fix it than to replace the item as a whole.
I am curious as to which manufacturer this is that makes tellies that conk after just ten months.