$username = "ad-domain\admin"

$Password = "mypassword"

$pwd = $Password | ConvertTo-SecureString -asPlainText -Force

$credential = New-Object System.Management.Automation.PSCredential($UserName,$pwd)

$Domain = "ad.domain.com"

Add-Computer -DomainName $Domain -Credential $credential –Restart

$username = "ad-domain\admin"

$Password = "mypassword"

$pwd = $Password | ConvertTo-SecureString -asPlainText -Force

$credential = New-Object System.Management.Automation.PSCredential($UserName,$pwd)

$Domain = "ad.domain.com"

Remove-Computer -UnjoinDomaincredential $credential -Force –Restart