New-Password.ps1

<#
.SYNOPSIS
    Generates a password
.PARAMETER Length
    Number of characters that should be in the password
.PARAMETER NonAlphaMinCount
    The minimum number of non-alphanumeric characters (such as @, #, !, %, &, and so on) in the generated password
.NOTES
    [email protected]
#>
[CmdletBinding()]
param (
    [Parameter(Mandatory=$false)]
    [ValidateRange(1,128)]
    [int] $Length = 15,

    [Parameter(Mandatory=$false)]
    [ValidateRange(0,8)]
    [int] $NonAlphaMinCount = 2

)

$assemblyName = 'System.Web'
Try {
    Add-Type -AssemblyName $assemblyName -ErrorAction Stop
    if ('System.Web.Security.Membership' -as [type]) {
        [System.Web.Security.Membership]::GeneratePassword($Length,$NonAlphaMinCount)
    }
    else {
        Write-Warning '[GeneratePassword] method not available (requires full .NET CLR).  Cannot create new password.'
    }
}
Catch {
    Write-Warning "Unable to load required assembly [$assemblyName]."
    return
}