Powershell - windows 2008 r2 - how to change IIS [application user (pass-through authentication)

Open Powershell on the IIS server, Run the following:

add-pssnapin WebAdministration

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Then run this:

set-webconfigurationproperty "system.applicationHost/sites/site[@name='Default Web Site']/application[@path='/']/virtualDirectory[@path='/']" -name username -value ''user@domain.com"
set-webconfigurationproperty "system.applicationHost/sites/site[@name='Default Web Site']/application @path='/']/virtualDirectory[@path='/']" -name password -value 'password'

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what do I do when I get an error: " The Windows PowerShell snap-in 'WebAdministration' is not installed on this machine."
pssnapin-webAdministration-error.tiff

For both solutions, I am getting this error:

The term 'Get-WebConfiguration' is not recognized as the name of a cmdlet, function, script file, or operable program.

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The term 'Get-WebConfiguration' is not recognized as the name of a cmdlet, function, script file, or operable program.
Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
At line:1 char:21
+ Get-WebConfiguration <<<<
    + CategoryInfo          : ObjectNotFound: (Get-WebConfiguration:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException

To me it looks like the "WebAdministration" module is installed...When I run Get-Module -ListAvailable

PS C:\Windows\system32> Get-Module -ListAvailable

ModuleType Name                      ExportedCommands
---------- ----                      ----------------
Manifest   ActiveDirectory           {}
Manifest   ADRMS                     {}
Manifest   AppLocker                 {}
Manifest   BestPractices             {}
Manifest   BitsTransfer              {}
Manifest   PSDiagnostics             {}
Manifest   ServerManager             {}
Manifest   TroubleshootingPack       {}
Manifest   WebAdministration         {}

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Are you running Powershell as admin?

Thanks, I needed to close the PS terminal and re-open it. Then I was able to bring in the WebAdministration module.