Unlink a GPO and delete it.

UnlinkAndDeleteGPO.ps1

#
# If given GPO is linked to any OU, it deletes the links and then attempts to delete the GPO.
#
function Delete-GPOByName 
{
	param(
	[string]$GPOName,
	[string]$DomainName
	)	
	
	$error.clear()	
	$MyGpo = New-Object -comObject GPMgmt.GPM
	Write-host "Delete-GPOByName: Created new GPM object"   
	
	$MyGPConstants = $MyGpo.GetConstants()
	$MyGPDomain = $MyGpo.GetDomain($DomainName, "", $MyGPConstants.UseAnyDc)
	Write-host "Delete-GPOByName: Created new GPDomain object"
	
	$SearchCriteria = $MyGpo.CreateSearchCriteria()
	$SearchCriteria.Add($MyGPConstants.SearchPropertyGPODisplayName, $MyGPConstants.SearchOpEquals, $GPOName)
	$SearchResults = $MyGPDomain.SearchGPOs($SearchCriteria)
	Write-host "Delete-GPOByName: Search to find $GPOName returned $($SearchResults.Count) results"
	
	foreach($GPO in $SearchResults ) {
		$SafeTodeleteGPO =  $true;
		Write-host "Delete-GPOByName: GPO ID for $GPOName is $($GPO.ID)"
		$GPMGPO = $MyGPDomain.GetGPO($GPO.ID)
		
		$SearchCriteria1 = $MyGpo.CreateSearchCriteria()
		$SearchCriteria1.Add($MyGPConstants.SearchPropertySOMLinks, $MyGPConstants.SearchOpContains, $GPMGPO)
		$SearchResults1 = $MyGPDomain.SearchSOMs($SearchCriteria1)	
		Write-host "Delete-GPOByName: Search to find links returned $($SearchResults1.Count) results"
		
		foreach($link in $SearchResults1)	{
			Write-Host $link.Path
			$GPOLinks = $link.GetGPOLinks()			
			foreach($gpolink in $GPOLinks) {
				if($gpolink.GPOID -eq $GPO.ID)
				{
					Write-host "Delete-GPOByName: Found link for $($GPO.ID), deleting link"
					try {
						$gpolink.delete()
						Write-host "Delete-GPOByName: Link deleted successfully"    						
					}
					catch {
						Write-host "Delete-GPOByName: Exception during delete operation"    
						$SafeTodeleteGPO = $false
					}
				}
			}			
		}		
		
		if($SafeTodeleteGPO)
		{
			Write-host "Delete-GPOByName: Safely deleting GPO"
			try {
				$GPMGPO.Delete()
				Write-host "Delete-GPOByName: GPO deleted successfully"	   
			}
			catch {
				Write-host "Delete-GPOByName: Exception during delete operation"   
			}
		}
	}
}

# Sample Usage:
# Delete-GPOByName -GPOName "NewTest GPO" -DomainName "testdom.com"