My tv was nothing but snow and wouldn't respond to attempts to change the channel.
I tried the power on-off business on the tv and also on the set top box. I was already getting stressed out over having to deal with telephone tech support.
I have Verizon FIOS service and remembered that there was a capability of checking out the tv from the computer.
Started right up selected tv from the menu and noticed quick things you can do.
Selected no picture and it asked me the basics - is the power on??
Is there any picture or just on certain channels? No - nothing.
It then checked the signal into the house and the set top box and said there were no problems there.
Next it said to check a button marked Input on the remote. Eureka!
All I can think is that it accidentally got pressed while using the remote.
That simple little thing could have cost me well over an hour on the telephone. It was basically just a few minutes on the computer and a little running up and downstairs because the tv is downstairs and the computer is a desktop that is upstairs.