You can do what you want. You need a multiboot solution. (You can have any combination of windows versions, linux, solaris, etc, all on the same computer, and boot any of them.)

This article is specific to Windows.

http://windowshelp.microsoft.com/Win...4c0201033.mspx

You might want to create a separate partition for your data and documents so they can be accessed easily from either version of windows. Either way, you can still access them. Putting them on a separate partition makes it easier, and you don't have to mess with the other OS root drive.

Here's another article on how to add XP dual boot to a system installed with vista first:

http://apcmag.com/how_to_dual_boot_v...step_guide.htm

The interesting part there is that when you install XP, it will overwrite the boot record, so you have to restore it and fix it up. It's all in the instructions.


-David