Check your $env:PSModulePath and verify that it contains C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules
Verify that this file exists: C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\WindowsUpdateProvider\WindowsUpdateProvider.psd1
(get-module -ListAvailable windowsupdateprov*).path
(get-module -ListAvailable windowsupdateprov*).ExportedCommands
PS C:\WINDOWS\system32> (get-module -ListAvailable windowsupdateprov*).path
C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\WindowsUpdateProvider\WindowsUpdateProvider.psd1
PS C:\WINDOWS\system32> (get-module -ListAvailable windowsupdateprov*).ExportedCommands
Key Value
Get-WUAVersion Get-WUAVersion
Get-WULastInstallationDate Get-WULastInstallationDate
Get-WULastScanSuccessDate Get-WULastScanSuccessDate
Get-WUIsPendingReboot Get-WUIsPendingReboot
Install-WUUpdates Install-WUUpdates
Start-WUScan Start-WUScan