Hello,
Instead of reformatting and setting your computer up for dual booting Vista and XP (as XP must be installed prior to Vista in order to work), I would suggest using
Microsoft Virtual PC 2007. This will allow you to create a virtual hard drive and share your actual system resources in order to create a virtual computer within your own.
Using this, you could install Windows XP onto a virtual hard drive which you could open and close at any time you wish. This is a lot better than dual booting your system and losing any data (as well as the time required to set it up) in the process. Not to mention, it's a lot safer.
Vincent P.
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