Do your homework. Check compatability on hardware and software. If you get Windows XP, you'll most likely need to update or replace your Antivirus and/or Utility programs, and maybe even your CD burner software. Are you prepared to invest that money? Before you decide on Windows XP Home or Pro versions, research. Do you need the extra stuff in the Pro version? Most average users do not. If you don't need the stuff, save yourself $100. If you're ready to make the plunge, do some advanced prep work. Find the Windows XP version of all your hardware drivers. Find any available updates for your software. Backup all important data. Once you've done your prep work, you're ready. You might want to wipe your hard drives and reinstall everything from scratch. Once Windows XP is installed, you want to immediately go to the Windows Update site and take any updates available. Yes, Immediately!