Microsoft requires you to register, or activate, the XP Home Edition either online or by phone. The Professional version, though, does not require you to activate as I would assume because the target consumers for that version is business users. Microsoft says during the activation, the product sends out special BIOS information pertinent to only that system. My bet is, though, that there are already ways around this all over the net.

While we are on the subject, I would just like to slam the stupidity of Microsoft for not including the Remote Assistance feature in the Home Edition of XP. They made such a big deal about being able to finally help friends and family right from your house with XP. This will only be the case if friends and family are willing to dish out an extra $100 for the Pro upgrade rather then the Home Edition. It's too bad VNC doesn't use compression...