Windows 10 start up menu how to reinstall ShellExperienceHost, Cortana?

I have problem with Windows 10 start up menu. I visited this page https://support.microsoft.com/en-us/help/12385/windows-10-troubleshoot-problems-opening-start-menu-cortana and tried the troubleshooter. It says

Required applications are not installed correctly. 

"Microsoft.Windows.ShellExperienceHost" and "Microsoft.Windows.Cortana" applications need to be installed correctly. 

Troubleshooter did not fix these problems. Can someone tell me how to install these applications manually?

Start PowerShell as Administrator. PowerShell.exe is located in this folder:

C:\Windows\System32\WindowsPowerShell\v1.0

Right-click PowerShell.exe and click Run as Administrator.

Execute these two commands:

Get-AppxPackage Microsoft.Windows.ShellExperienceHost | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}

Get-AppxPackage Microsoft.Windows.Cortana | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}

This reinstalls ShellExperienceHost and Cortana.

Src: Start menu and Taskbar Stuck in Windows 10. How to Fix it?

w32sh's answer has the standard way of reinstalling these. However, for me this didn't work at all, nor did any other suggested solutions. My issue came with the taskbar, start menu and W10 apps being unusable.

If w32sh's solution doesn't work for you, have a look at my answer here.