Not quite but sort of. When I installed Vista I pulled all my other drives (XP) except one, and used that one for Vista. Now I'm thinking of going to a dual boot system, and to save having to reinstall Vista I have an option in the BIOS where I can choose which hard drive boots first, if I were to use this could it cause any grief with my XP files? Whichever OS was running would be able to "see" the other drive, but wouldn't this be the same as a regular dual boot, I've never used dual boot before so I don't know. Ray