kenwood

ok so i had xp than i put on vista ultimate and when first time starting up it froze again and again at the loading screen where the green bar passes and it says vista. So i took out my dlink dwl-g550 wireless nic and put in my g510 and it booted up but internet wont work so i figured theres no drivers. Scouted out some drivers for the dwl-g550 for vista popped the card back in and suddenly it loads internet works. OK so than i put to sleep at night and turn on in morning wont load again. So i than took the card out and partitioned a space for xp and reinstalled it now i have both on but when i reboot it only boots xp shouldnt there be a menu asking what os i want? How can i get this?