My sound was all right. Then I followed the instructions here
https://forums.opensuse.org/english/get-technical-help-here/how-faq-forums/new-user-how-faq-read-only/407184-multi-media-restricted-format-installation-guide.html
as i thought it would be good to enable some restricted formats etc.
Now, the skype sound works fine and the test of the sound card, but I have no sound in online radio, applications etc. The speaker on the lower right side shows that the volume is at 0% and it does not allow me to increase it.
My alsa specifications (if they are still valid) are here:
http://www.alsa-project.org/db/?f=3025588da534e3460d87445a5345b559d162340c
Thank you,
Vasilis