OK, lets find out if it is something with the user account or not.
As a test, create a new local account on the system and then log in with that account and see if the store works for the new user. That will tell me if it is a profile problem or if it doesnt work either, if it is something wrong in the system itself. 
Shane
Hi Shane,
I also have this problem with Windows Store and Metro Apps (including Photos and PC Settings which I could find a fix), except when I create another test user everything seems to work just fine. At first not even my 'modern PC Settings' would work, then I found this command and could change my pc settings once again:
powershell -ExecutionPolicy Unrestricted Add-AppxPackage -DisableDevelopmentMode -Register $Env:SystemRoot\ImmersiveControlPanel\AppxManifest.xml
After running this command and concluding it did work for the settings app, I started 'playing around' with it and trying to register other apps such as Photos, Camera, FileManager and even the Win Store itself. Turns out it also did fix those apps, but I still can't install any modern apps from win store and there are a couple apps which couldn't be fixed after I ran this command using 'ProgramFiles\WindowsApps\*\AppxManifest.xml' as path.
I also ran your Windows Repair Tool (latest version available) as suggested and it didn't fix those apps.
Please, any help?
