varcoris

ALWAYS install the older operating system first and work your way to the newest. The bootloader files are different for each version but backwards compatible. So, if you install XP first, Vista knows how to let it run, but if you install XP second, it does not know how to let Vista run...

You know, there are a ton of posts asking how to get an unattended Windows installation from a USB device. Sounds like that is what you have accomplished, care to share?