Changing the XP Professional Corporate Product Key

Step 1:

Go to Start> Run> type in regedit.  Navigate to:  HKey_Local_Machine\Software\Microsoft\WindowsNT\Current Version\WPAEvents.  Right click on OOBETimer and select 'Modify Binary Data.'  *Change at least one of the values (just delete one or two of them, see pics for details) and close the Registry Editor.  *note:  It's good practice to export any keys/values you modify in your registry before actually doing it in case you muck something up and need to put it back.  You can do this by right clicking on the folder WPAEvents and selecting "Export."  Just save the yourname.reg file somewhere handy.

Step 2:

Go to Start> Run> type in:   %systemroot%\system32\oobe\msoobe.exe /a

Select the second option, "Yes, I want to telephone..." and then click next.  In the next window click on the Change Product key button.  Type in your new product key (Corporate Only).  This will take you back to the previous window, just exit out and reboot your system.  See pictures for details.

Step 3:

After you reboot, go to Start> Run> and type in (again):   %systemroot%\system32\oobe\msoobe.exe /a

You should now see this:

That's it.  Enjoy.