XP Home and XP Pro
My folks just got a new computer running XP Home. I’m installing stuff on it and happily noticed that the Messenger Service is turned off by default. This is the service that allows Messenger Spam. :-)
I tried doing an upgrade install on a client’s computer from XP Home to XP Pro. The Upgrade install failed miserably. Midway through, the upgrade got stuck, churning over one point and restarting. I had to install Pro from scratch. Hurumph! A few months ago, I tried doing an upgrade from 2000 Pro and had a similarly crappy experience :-(