|Your post is a bit confusing. The only way you can install an operating system (such as Vista) onto another operating system (such as XP) is to use a Virtual Machine. Most likely the XP hardware would not be up to it and a Virtual Machine would not put you in a position to restore XP if that is what you intend.|
You can dual boot to two different operating systems but again it is a matter of whether the hardware is suitable and I can't see where this would get you either.
If you mean you want to replace XP with Vista then again the hardware is unlikely to be suitable. In any event it would not authenticate with MS if it was saved from different hardware.
Let us know exactly what you have got and what are trying to do, although if I have read you correctly you are trying to do the impossible.
Always pop back and let us know the outcome - thanks
message edited by Derek