before replacing anything, when u try to start the car, do u hear any kinda of sounds? do u hear a sound of metal hitting metal? or do u hear something trying to rotate?
if u hear the 1st sound then your alternator isnt working coz the pinion is hitting the flywheel without being rotated
but u hear the 2nd sound, then your soleniod is either gone bad or the pinion is jammed and doesnt connect with the flywheel
in either cases, have ur starter motor checked
hope i helped