Thanks Wombat. This jives with the information I found in Microsoft TechNet. But then I saw the thread started by William_Wilson. See link below. Is there something I'm missing? The info I gathered so far, is that XP will replace the Vista boot loader, which will need to be repaired once the XP installation has completed. XP will also find itself on a E: drive, which is not a problem for it, except for some applications hard-coded to install on a C: drive. This does not affect me, as I only want to keep XP as a reference tool for my tech support work. If there is no other choice, I will install XP on the spare drive I have, but this will require that I disconnect the drive when not in use, something I would have preferred to avoid.