I installed Pot Player using Wine in Elementary OS 0.4 Loki, it didn't work so I uninstalled it. The icon was still in the applications list, so I removed Wine thinking that it might help, I followed this forum. After that I could hear no sound, no sound at all, no sound in vlc, videos and other players and no notification sounds at all. I can't even hear any sound in sound test, even in bluetooth speakers or headphones. How to get it back? I'm running Elementary OS Loki.
Step 4 of this doc at https://help.ubuntu.com/community/SoundTroubleshootingProcedure includes installation and starting pavucontrol and helped me restore sound on a Dell Lattitude laptop. I had system sounds like trash and test front left/ front right but Noise Music player and videos on the browser did not have audio.
In Elementary Loki systems settings I no longer have Sound. Not sure what I installed to loose it. Anyway Jorge R. Marin's solution above to install pavucontrol via Terminal got sound back on my Toshiba Satellite laptop running on Elementary Loki. Thank you Jorge.
sudo apt-get updateand afterwardssudo apt-get install pavucontrol