I really want to test Windows 7 to see its features and how well it works on a Mac Pro. I have a 150GB partition Bootcamp partition of Windows XP Professional 32-bit on my 500GB WD HDD. I have a genuine Windows XP Pro install disc from Microsoft. My question is, if I install Windows 7 and for some reason I don't like and want to go back to Windows XP, will I be able to install XP over Windows 7 or will the product key not work. I want to be 100% sure that XP will work again after installing Windows 7. Is there a possibility to have a multiboot windows system in bootcamp. Also how can I burn an ISO file like MS says on their website?