XP key changer is a way to update the product activation code, also known as a product key, for the Windows XP Professional operating system. This action may be necessary in the event a product key intended for a single computer has found its way onto more than one computer in a corporate network.
In a few corporate network environments, system administrators have been known to deploy single-user product keys (which are publicly available on the Internet) on multiple computers. If such a key exists on a corporate computer without its user's knowledge, the key is said to have been "leaked." This can cause problems when the user tries to install updates to the operating system. An affected user can update the product key without having to purchase and install a completely new individual copy of Windows XP if problems of this sort are encountered.