This CD contains 9 versions of Windows XP with Service Pack 3 integrated, straight from Microsoft. Several files have been patched, uxtheme.dl_ (for custom themes), sfc_os.dl_ (for System File Check), and tcpip.sy_ (to enable more TCP/IP connections). You can find the untouched versions of all the files in the TOOLSUNPATCHED folder found it the root directory of this ISO. This release is ISO because of the special filesystem required. ISO s can be made of any of the versions of windows on the CD. There is a special version of Windows XP Media Center 2005, an Integrated ISO which can be created. This integrated ISO s has both CD s of Media Center in one for easier installation.