You can install XP Pro over XP Home. Upgrade
Clean installations in my opinion are better because there is usually lots of stuff floating around in the registry and hard drive that would better off removed.
The downside clean installations take more time and effort.
Insert the Windows XP CD into your computer's CD?ROM drive.
After your computer automatically launches the CD, click Install Windows XP.
When you're asked to choose the type of installation you want, select Upgrade, and then click Next.
I have XP Home & planning to purchase XP Pro. My question is ...Can I install XP Pro over XP Home or must I uninstalled XP Home then installed XP Pro.This means I have to backup the HD, uninstall XP Home, install XP Pro & then install the Backup.