Hi again Roman,
I did exactly that to no avail. Actually, what I find weird is that the playback device is called "Digital Output ()", with the "()" including nothing inside. Sometimes, when I select that device, the sound comes from the laptop, but often it does not come from anywhere at all.
I think I have done all I could to try to make it work. I used to be able to mirror this very same laptop with picture/sound on my old TV (also Samsung) and I never had any problems.
Thanks again, though.