HKEY_LOCAL_MACHINE is the hive in the Windows Registry where you’ll find the registry keys associated with the Power User Menu shortcuts. “The Power User Menu can be customized by rearranging or removing shortcuts within the various Group folders contained within the C:\Users\\AppData\Local\Microsoft\Windows\WinX directory.
Tim Fisher also wrote an article referencing the Registry Location for the Power user settings. This appears to be the only direct customization option for the Win+X menu built into the system interface. You can perform a similar effort within Windows 10, albeit more easily by simply navigating to Settings > Personalization > Taskbar and then selecting the ‘Replace Command Prompt with Windows PowerShell …’ from the list of options. Tim Fisher wrote an article about replacing the Command Prompt with Windows Power Shell using the control panel in Windows 8.1. Recent students asked for a means to modify the list of options available to users within the WinX Menu prior to deployment of Windows 10.
The WinX menu is available in Windows 8, 8.1 and Windows 10. The latter naming convention is associated with the ability to launch the menu by using the Windows key + the X key ( Win + X). The administrative menu available by Alt-Click (right mouse click) of the Start menu icon is also referred to as the Power-user or WinX menu.