Also called the WinX menu due to the keystroke to open it: Win-x
This happens when a handful of file and folders become corrupted for some reason. It’s an easy fix as long as you have access to another working Windows 8/8.1 computer, or can create a new user account on the affected computer.
What you need to do is copy these 3 folders; “Group 1”, “Group 2”, “Group 3” in c:\users\[user]\AppData\Microsoft\Windows\Winx\ from a working computer or working user profile on the same computer, and overwrite them in the same location under the user profile folder that isn’t working.
You may have to log out and log back in, or just reboot, for the menu to start working again.