I got slightly farther but it's still not working for me, and I think it's an IIS versus IIS Express problem.

What I did:

run appwiz.cpl
select Windows Features on the left hand side.
In the tree item: Internet Information Services
In the Tree item: Web Management Tools
Select the checkbox on this tree item: IIS Management Scripts and Tools


In a command prompt:
Powershell
Import-Module WebAdministration (this succeeded!)
Stop-WebSite "Websitename"

This gets an error message:

stop-webitem : Cannot find path 'IIS:\Sites\Websitename' because it does not exist.

Note that it says: IIS: there and not IISEXPRESS.