I tried many solutions listed above and finally found the one that worked for me:
I used this solution through steps 1 and 2 to fix this problem! Did not need step 3.
Problem:
The Windows Start button, Search (Cortana), and the system tray (including Action Center & time/date) all display menus when right-clicked, but when left-clicked, nothing happens. Also, two icons in taskbar were missing (but can be clicked and work, as well
as can be hovered over and display the app, even though the icon is blank): icons for store and edge.
SOLVED: Fix Windows 10 Start Button Does Nothing in 10 Minutes
http://www.urtech.ca/2015/09/solved-fix-windows-10-start-button-does-nothing-in-10-minutes/
BTW, as a bonus side effect, this also allowed my pc to operate much more quickly when opening and closing apps, related to this issue.
Thank you to the person herein who provided the solution (so glad this is fixed for me). I hope this works for everyone.