Could you try the following:
Press Windows Key + R to open the run dialouge
Run the following command to open an administrator PowerShell window: PowerShell -ExecutionPolicy Unrestricted
Then paste the following PowerShell command into the resulting window and press enter: Get-AppXPackage -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}
This will take a while and some errors may flash up this is normal.
Once it’s complete reboot the computer and see if you’re able to right click on the task bar again, let us know how you get on!