dual boot vista and xp
 

i have this vista installed on my compaq, and i want to dual boot it with xp, but i don't have the vista dvd because it is preinstalled on my laptop. is it possible to dual boot?

theoretically it is possible, you will need to install a 3rd party boot loader unfortunately. Since you will be unable to take control from XP and give it to Vista. Depending on where you got your computer you should go and ask for a copy of Vista. I'm pretty sure it's illegal to not supply you with one. Even if the copy is limited it should be good enough to let you run bcdedit