How to change Windows XP Product Key

To change the product key Windows XP, for example, to install Service Pack 1 must follow these steps.

We must get a valid key other than F, D, ....

We click on the Start button and then on Run, then type regedit and click OK button. Once we are in the Windows registry we move through the next key. (in many cases do not need this step, so we would go directly to step 4)

HKEY_LOCAL_MACHINE \ Software \ Microsoft \ Windows NT \ CurrentVersion \ WPAEvents

Double click on the key OOBETimer, and delete hex value CA, and close regedit.

Now we click the Start button and then on Run, type exactly this oobe / msoobe / ay activation screen appears Windows XP, select activation by phone, and click on Change product key and enter the new password and click update.

Most likely to tell us that the key is not valid, but we should not ignore, close everything and reboot.

Once rebooted again press the Start button, then Run, type new oobe / msoobe / a and see how shows a screen that indicates that the product is already activated.