Hi John, I could not see anything about dual booting there it is all about upgrading say going from Windows Vista 32 to 64.
My Personal preference is not to use dual booting as if e.g. if a disc drive fails and one has two operating systems on it and their respective software and files, one has doubletrouble, I think a much better solution is mobile racks, with seperate hard drives for different operating systems. That way you can have say Windows XP 32 Professional on one drive, Windows XP 64 Professional on another drive and Windows Vista 64 on another drive and the three operating systems whilst sitting in their racks in the computer are never connected at the same time, so you can't get a software problem spilling over from one operating system to another like you can when you have a number of operating systems daisy chained together.
Best and Warm Regards
Adrian Wainer