Quote: Originally Posted by
acdcfan 
None whatsoever.... Just make sure you fix Boot.ini file because for some reason XP tends to destroy Vistas boot loader...
Oh yes! Since you've already installed Vista,When you install Xp it will overwrite the Vista bootloader and you'll have only XP.But you can get Vista back by booting frm the Vista DVD and reinstalling the bootloader.you can then dual boot XP 32 and Vista 64.
Theres are many detailed Tutorials available on this,search.