Windows XP has been the single best thing that Windows has come out with in last 15 years. There have been millions of users who have admired and relied on Windows XP. Though, I will talk about the less fortunate ones among the lot. I am talking about Windows XP Home users. I donno why they chose it but I am sure that they at once wanted to change it to Windows XP Professional. So here is a scope for them to change Windows XP Home to Windows XP Professional.

Trick

1. Copy the root directory and the i386 directory of the WindowsXP CD to your hard drive.
2. Extract the Bootsector of your Windows XP CD. You can use BBIE to do this.
3. Click START–>RUN
type regedit
4. Highlight HKEY_LOCAL_MACHINE

5. Click FILE–>LOAD HIVE and select the Setupreg.hiv file
This file is located in the i386 folder. Use the one you extracted to your hard drive from your Windows XP CD.

6. Locate the following registry key:

HKEY_LOCAL_MACHINE\Homekey\ControlSet001\Services\setupdd

7. Edit the DEFAULT key and change the following values:

01 to 00
02 to 00

8. Change the name to the value HOMEKEY to anything.

9. Locate the following registry key:

HKEY_LOCAL_MACHINE\Homekey\ControlSet001\Services\setupdd

Edit the DEFAULT key and change the following values:

01 to 00
02 to 00

10. Highlight HOMEKEY and select FILE–>UNLOAD HIVE

You can now burn the data on your hard drive to a CD to make a new Windows XP CD. Then use the CD to install Windows XP. Be sure to make the CD bootable.

[[Note: we don't encourage you to use these techniques(taken from technipages.com) because we do not practice them ourselves. But if you do, don't forget to leave a feedback and also before playing with the registry do not forget to make a backup]