Registry change for XP Home to XP Professional

I needed a way to be able to install a legitimate XP Professional Open-License version over top of an XP Home without losing programs and data, etc.

This is the registry hack to do it:

Open Registry Editor (regedit).
  1. Navigate to HKEY_LOCAL_MACHINE/SYSTEM/ControlSet00X/Control/ProductOptions, where ControlSet00X is the one with the highest number.
  2. Delete the ProductSuite registry key.
  3. Then, create a new DWORD value and named it as Brand.
  4. Set the “Brand” value data as 0.
  5. Reboot the system.
  6. On boot up after the BIOS screen, press F8 to display Windows XP Startup Menu.
  7. Choose Last Known Good Configuration (LNG) and hit Enter.
  8. Voila! Now it's XP Professional (as far as the XP Pro installer is concerned).


(N.B: I am in no way condoning doing this for illegitimate purposes but purely to save yourself time in not having to save the customers data and re-install programs)