How to repair windows vista ultimate?

i had installed windows vista on drive C: and windows XP sp2 on drive D:.

but i infected by virus in xp and i had to install xp again on drive d, but when it completes i knew that my vista option that let me choose which version of windows to load is not shown anymore.

when i start computer it goes to xp.

my vista DVD is not bootable.

please give a solution to repair vista in xp

thanks

How to repair windows vista ultimate?auto protect

Go into XP. Insert the Vista distribution disk. If you have AUTORUN, just wait for it to ask you if you want to install it. Go from there.