Are People Thrown In To Hell For Their Sin?

did Jesus Christ pay FOR ALL SIN? or just for THE SINS of THOSE WHOM WERE HIS to begin with?? what does it mean when THE BIBLE TELLS US ONE MUST BE BORN AGAIN???? HOW IS ANYONE BORN AGAIN to begin with?? is SALVATION DEPENDENT ON WHAT WE DO? or in BELIEVING and ACCEPTING WHAT Jesus Christ DID IN...