How was Lord Vishnu born?

According to Vishnu Puran, Lord Vishnu sows the seeds of a new Yuga by giving birth to Brahma, Mahesh and Lakshmi. Brahma gives birth to Saptarshi and these impart education and knowledge to humans
Lord Vishnu or PalanKarta meaning sustainer, protector and preserver - creates universe from Himself. He existed before the creation of the universe and everything will become a part of Him.
Vishnu Puran asserts that after pralaya takes place, only Vishnu survived and then helped to restore the divine balance. Lord Vishnu contributed to the resurrection of the universe by giving birth to Brahma from the navel.