Problem surfaced again, Skype not the problem? This morning I entered Settings> Sound Output and found that I must toggle Speakers vs. Headphone. I hope I found the solution this time!
I had this problem but could not find a solution in Settings. Then I remembered that I had installed Skype a few days ago. Loaded Skype, turned on camera in Skype, did a sound test. Presto, problem solved! Alarming to have found the solution there!
Headphone not working in Dell Inspiron 5515