You would think that what works for XP would also work for server 2003. Although it is based on it they both have their own OS ID and software programed not to work on 2003 wont unless it is hacked. the perfect example is Avast by Awil. Their free version is set to not work on server 2003 to force you to but Avast server edition. Unfortunately it costs about $300 for one licence.