Users who upgraded their Windows 8 systems to Windows 8.1 are complaining that they are not able to launch any modern ‘metro’ app; add new users or open the ‘settings’ app by moving the cursor to top right corner of the screen.
Complaints are flowing in on Microsoft community forum with one users noting that “Store won’t open. It shows the splash screen, then a solid color screen. Nothing else happens. If I click anywhere, it goes back to the start screen.”
There are those who have also flocked TechNet reporting similar issues. One user notes “I recently updated to windows 8.1 and now nothing in the modern UI will launch. The store app, any of my installed apps, or even the “Change PC Settings” screen will load. All my apps have a little “x” on the bottom right corner of their tiles.”
Workarounds have been suggested by quite a few users like upgrading the graphics drivers and even running through all the troubleshooting steps in a different post, but users are claiming that nothing is helping.
The only thing that seems to resolve the issue for now is a clean install from start using a ISO downloaded from Microsoft Store rather than an upgrade to Windows 8.1.
I know that the UAC needs to be on in order to run metro apps. I’m not aware of the 8.1 upgrade affecting a users UAC level, but its worth checking before a complete reinstall. The UAC controls can be found by typing “UAC” at the Start Screen.
Also, towards the top of this page:
http://windows.microsoft.com/en-US/windows-8/what-troubleshoot-problems-app
There is an Apps Troubleshooter provided by Microsoft that might help.