If you need to reinstall Windows XP and you do not have the installation number (Windows XP Product Key), this program will read the necessary installation number from registry. If the Windows system does not work, reads the product key from the root of the injured system. Just connect drive with a malfunctioning system to the functional computer and select the root Windows folder, for example, E:Windows. The program finds the current Product Key and Product Key used in the first installation of the system. They may vary among by brands computers with pre-install system. Lite version shows incomplete Product Key from system folder.