how to change the Windows XP product key

If you would like to change the windows XP product key for some reason or other here is how to do it.
Before starting you should create a System Restore point in case something goes wrong.

Open the registry editor regedit by Clicking Start, Run and then typing regedit, and then click OK.
When in regedit look in the left pane then locate and then click the following registry key:
HKEY_LOCAL_MACHINE\Software\Microsoft\WindowsNT\Current Version\WPAEvents
In the right pane, right-click OOBETimer, and then click Modify.
Change at least one digit of this value by deleting or adding to it to deactivate Windows Click on OK and then exit the registry editor.
Now Click Start, Run and type the following command, and then click OK.
%systemroot%\system32\oobe\msoobe.exe /a
The activation window will open, Click on Yes, I want to telephone a customer service representative to activate Windows, and then click Next.
Click Change Product key at the bottom of the screen ,type the new product key in the New key boxes, and then click Update.
If you are taken to the previous window, click Remind me later, and then restart the computer.

The new key will now be in effect