I have suddenly lost all channels on my Sharp Aquos TV, it's giving a message 'no signal', although two other TVs in the house are fine. I have tried to reset from 'Factory settings' but it doesn't install anything. When I do 'channel scan' it shows no channels. I have tried pulling out the ariel and then re-inserting it, but no difference. I am a non-techno person, so any non-jargon help would be much appreciated. Thank you.