Windows 10 – Can’t launch programs via search bar

I've had this problem for quite some time now, and so far I've found no solution – but it's really beginning to get on my nerves.

Basically, when I search for a program via the Windows start menu (the search bar), I will get the correct results – but some programs I simply cannot open.

Example: I click on the start menu and begin typing "control panel". It will show me the control panel as a search result, but when I hit enter, or click on it – nothing happens. It simply stays there as if nothing happened.

This is the same with ALL apps except the "metro" applications from the Windows Store (whatever they call them now).

The problem began after I changed the system language from English to German, and even if I switch back to English, the problem won't go away again.
Here's what I have tried so far:

• Running sfc /scannow in an elevated Powershell multiple times.
• Reindexing the search via control panel multiple times.
• I've run lpksetup /u in an elevated cmd multiple times.
• I've killed Cortana and Windows Explorer.
• I've obviously run the "troubleshooter"
• I've made a new account for myself. It worked until I changed the language back to German.
• Running Get-AppXPackage -Name Microsoft.Windows.Cortana | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"} in the powershell
• Starting Windows in Safe Mode

If I right click on the item in the search results and try to launch it that way, it says the item is not found and asks me if I want to remove it from the list.

Any help would be appeciated 🙂

Thanks in advance