Black screen panasonic Viera TX- L47ET5E

Good evening everybody,

I guess that my TV is bugging.. do you have any idea about how to reset the TV?

Description of the problem:
I have turned on the TV (panasonic_Viera_ L47ET5E) the audio of the program is present without the video (I have black screen).

I have distinguished from the voice of each channel that I have only 6 programs instead of 45 (before the bug).

I have used the method of pressing Vol- and Menu of the remote for 5 seconds..
After trying that I have lost the audio too!!
Actually I have black screen and no audio...

Does someone encountered same problem as mine?

Thank you for your help.

Black screen panasonic Viera TX- L47ET5E