1. Purchase the conventional "Retail Upgrade Version" of Windows XP Pro.
2. Uninstall any third-party antivirus or firewall programs.
3. Disconnect all peripheral hardware devices, but not the monitor, keyboard or mouse.
4. While at your XP Home desktop screen, insert the XP Pro CD in the CD drive.
5. Select the default "Upgrade" option.... DO NOT SELECT "New Installation".
6. Defrag your drive after upgrading.
7. Reinstall your antivirus program & turn-on the firewall.
8. Visit the Windows Update website and download the necessary updates.
Note:
If you perform the upgrade procedure correctly, then your
files and programs should remain intact. However, it would
be prudent to perform a backup of your important files just in
case you encounter a revelation of "Murphy's Law".
--
Carey Frisch
Microsoft MVP
Windows XP - Shell/User
Be Smart! Protect your PC!
http://www.microsoft.com/security/protect/