mga sir/ma'am. panu ba to? etong pc ko 2 ang OS isang vista and windows 7.bali unang nainstall yung vista next is windows 7.tpos ni repormat ko yung sa vista wich is drive c.(windows 7 is drive e)tpos install ko na uli yung vista sa drive c. after successful installation nawala na yung boot up choices.pano ko kaya yun maibabalik, without reinstalling windows 7 nmn? thanks a lot po in advance.