I tried the following things with Win7:
- update audio drivers (from Panasonic website)
- update HotKey (from the Panasonic website)
I have not solved.
Audio is never heard from internal speakers (only in headphones works).
I started the NoteBook from a CD with Linux Ubuntu and the audio does not come out from the internal speakers (it only works from the headset even with Linux).
So I did HW diagnostics from the BIOS. The diagnosis says that the AUDIO TEST has passed but the beep is not heard from the internal speakers.
I think it is an internal failure, but it would be the first time in my life to see the internal speakers of a notebook broken (also in a rugged PC).