Function Test-UserCredential {   [CmdletBinding()] [OutputType([System.Boolean])]   param(     [Parameter(Mandatory=$true)] [ValidateNotNullOrEmpty()]     [System.String] $Username,     [Parameter(Mandatory=$true)] [ValidateNotNullOrEmpty()]     [System.String] $Password,         [Parameter()]     [Switch] $Domain   )     Begin {     $assembly = [system.reflection.assembly]::LoadWithPartialName('System.DirectoryServices.AccountManagement')   }     Process {     try {       $system = Get-WmiObject -Class Win32_ComputerSystem       if ($Domain) {         if (0, 2 -contains $system.DomainRole) {           throw 'This computer is not a member of a domain.'         } else {           $principalContext = New-Object -TypeName System.DirectoryServices.AccountManagement.PrincipalContext 'Domain', $system.Domain         }       } else {         $principalContext = New-Object -TypeName System.DirectoryServices.AccountManagement.PrincipalContext 'Machine', $env:COMPUTERNAME       }             return $principalContext.ValidateCredentials($Username, $Password)     }     catch {       throw 'Failed to test user credentials. The error was: "{0}".' -f $_     }   }}