How to change serial number used on Windows XP

Step 1


Open Start/Run... and type the command:
regedit and click "OK" (or press ENTER).


Go to HKey_Local_Machine\Software\Microsoft\WindowsNT\Current Version\WPAEvents,
on the right double click on "oobetimer" and change at least one digit of this value to deactivate windows.


Click "OK" and close the Registry Editor.


Step 2


Open Start/Run... and type the command:
%systemroot%\system32\oobe\msoobe.exe /a and click "OK" (or press ENTER).


This will bring up the "Activate Windows" window.


Check the option for "Yes, I want to telephone a customer service representative to activate Windows" and click "Next"




Step 3


Then click "Change Product Key" (don't enter any information on that screen)




Step 4


Type in the new key and click "Update"




The activate Windows by phone window will reappear at this point, just close it by clicking the X in the upper right hand corner


Step 5


Reboot your system and Open Start/Run... and type the command:
%systemroot%\system32\oobe\msoobe.exe /a and click "OK" (or press ENTER).


If you see "Windows is already activated" then everything is OK.