Change Windows XP Home to Windows XP Pro

Here's the detailes.

1. Copy the root directory and the i386 directory of the WindowsXP CD
to your harddisk
2. Extract the Bootsector of your WindowsXP CD
a) *IMPORTANT* At this point, you MUST install any service packs
by slipstreaming them in as it will be in impossible to install
them later.

3. Change 2 Bytes in i386\Setupreg.hiv :
a) Open Regedit
b) Highlight HKEY_LOCAL_MACHINE
c) Menu: File -> Load Structure -> i386\Setupreg.hiv

d) Assign an arbitrary name to the imported structure e.g. "Homekey"
e) Goto HKEY_LOCAL_MACHINE\Homekey\ControlSet001\Services\setupdd
f) edit the binary key "default" and change "01" to "00" and "02" to "00"
g) Highlight "Homekey" and select menu: File -> unload structure
4. Burn your new XP Pro CD

5. Install WindowsXP as usual. Your XP Home Key will work.