James over on his Views on Vista blog has an excellent article on detecting via a Group Policy WMI filter the VISTA or Longhorn Operating system. He has even gone to the trouble of creating the script for you !. By the way this is an excellent blog if you are looking good solid information about Vista, I am certainly going to add it to my link list. I was also reading his New sounds for Vista..........it is hilarious ! you got to listen to it !