Video tutorial for when sound icon stops working.
https://www.youtube.com/watch?v=vOQro_gq4BI
His instructions: Go to Task Manager (looks different on mine, but I just used Search to find the Task Manager. From there, followed his fix exactly... Easy as pie!
(The fix, in case video goes missing: On Task Manager, scroll down to "Windows Explorer" in the list, right-click and choose "Restart." Then minimize or close all windows, go to your desktop, right-click and "refresh." (I did it 3 times, because he did--not sure if that's necessary).