By the way as vivekanada said hinduism is not based on any central authority, ram, krishna and many others are just those who uphold the vedas( which is actually the basis of hinduism..).. if you disprove the existence of jesus --christianity fades... if one disproves the existence of mohammed-islam fails... if one disproves the existence of zoraster or any other religious prophets.. that religion fails...
but that is not the case with hinduism... even if u believe in ram or not hinduism is based on vedas which is considered to be Apaurusheyatva which means it is of divine origin...