xml

[xml]$xml2 = @'
<?xml version="1.0" encoding="utf-8"?>
<unattend xmlns="urn:schemas-microsoft-com:unattend">
  <settings pass="specialize">
    <component name="" language="neutral" versionScope="nonSxS" xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State">
      <Identification>
        <Credentials>
          <Username>
          </Username>
          <Domain>
          </Domain>
          <Password>
          </Password>
        </Credentials>
        <JoinDomain>
        </JoinDomain>
        <JoinWorkgroup>
        </JoinWorkgroup>
        <MachineObjectOU>
        </MachineObjectOU>
      </Identification>
    </component>
    <component name="Microsoft-Windows-" xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State">
      <ComputerName>
      </ComputerName>
      <ProductKey>
      </ProductKey>
      <RegisteredOrganization>xxxx Group Headquarters, IT Services</RegisteredOrganization>
    </component>
  </settings>
</unattend>
'@
$registeredorganization = "PowerShell.org"
$xml2.unattend.settings.component.registeredorganization
($xml2.unattend.settings.component | Where-Object {$_.Name -eq "Microsoft-Windows-"}).registeredorganization = $registeredorganization
$xml2.unattend.settings.component.registeredorganization