Dual Boot Problem Windows Vista gone from Dual Boot with XP

hii,,
i have installed windows XP with dual booting of windows vista but now it is not showing windows vista in the boot menu??
what should I do to rectify the problem??

Before answering, can you tell me what really happened when ur Vista disappeared from Boot options ?

PS: Try to keep your TOPIC title little more explanatory .

well i guess ther first operating system was windows Vista and you tried to install XP and make it double bootable right?

This will solve ur problem.
Download and Instal EasyBCD. Just remember that if u install in XP then download EasyBCD 1.52, or if u want for vistal then go for any new version.
Try using the software u will find everything about ur problem. For any more help, u can consult me again.