Google for GAG boot manager. Download it but don't install it Create a new partition that you want to use for XP. Once you have the new partition then install GAG noot manager. It install on the 8MB of lead in on every harddrive and creates a DOS environment so as to control/hide the boot files of each operating system. Using GAG there is no over-riding of the individual operating systems MBR (master boot records). Gag will allow you to install XP without issues of coruption from VISTA.