text: I assume you are talking about Windows XP SP2. It is so much better than service pack 1 because it includes so many more security and performance fixes than sp1. It takes up so much space because it is a lot of fixes, has some new features, and it has an uninstaller. Yes, you can roll back to SP1, so it needs a lot of backup files. Don't ask me why, I don't get it.\nThe new features are Win XP yelling at you if you don't have Firewall or Antivirus software, or if it is off or outdated. Also, it has a lame firewall. Still better than nothing though.