In my old computer i had multiple hard drives, one with windows 7, one with windows xp and more for storage. I was able to go into bios and change boot drive in order to go from windows 7 to xp and back if i wanted. Now with my new computer it will not even react to any boot order that I select, basically I have to leave it on Windows Boot Manager in order to start windows 7 in the first place, and in order to start up in XP i have to manually unplug the windows 7 drive. So frustrating since i have to use both OPs, some programs from work only work with windows XP, I tried windows 7 XP mode, but some programs don't work with it.