How to upgrade WinXP home to WinXp Professional

There is a registry trick to convert and Upgrade Windows XP Home to Windows XP Professional without using the os software, follow procedure below.

1. Open registry edit (regedit).
2. Navigate to HKEY_LOCAL_MACHINE/SYSTEM/ControlSet00X/Control/Product Options, where ControlSet00X is the one with the highest number.
3. Delete the ProductSuite registry key
4. Then, create a new DWORD value and named it as Brand.
5. Set the "Brand" value data as 0.
6. Reboot the system.
7. On boot up after the Bios screen, press F8 to display Windows XP Startup Menu.
8. Choose Last Known Good Configuration (LNG) and hit Enter.

Windows XP will start up as usual. After logging into the desktop, check the
system properties to verify that it's now Windows XP Professional.