Change XP Serial Number

So, there are a lot of posts out there on various ways to do this, but I have found this method to be the easiest and most successful.

1. Click Start > Run
2. In the Open box, type regedit and hit enter.
3. Go to the following registry key:
   HKEY_LOCAL_MACHINE\Software\Microsoft\WindowsNT\Cur rent Version\WPAEvents
4. In the right pane, double click OOBETimer, and change the value of any one of the digits (you can change it to whatever you like). You have now just deactivated Windows.
5. Go to Start > Run.
6. In the dialogue box type:
   %systemroot%\system32\oobe\msoobe.exe /a
7. Select "Yes, I want to telephone a customer service representative to activate Windows" and then click next.
8. Click "Change Product key".
9. Type in the new product key and then click "Update".
10. If you return to the previous window, click "Remind me later", then restart the computer.