How to change the serial number used in Windows XP, Valid for XP Corporate

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.