Wendy,
Try replacing the battery terminal wires on both the ground and the positive of the battery (black and red wires) with new. Current is not always able to flow through old, deteriorated or frayed wiring. That is the only link in the chain so far that you have not replaced.
After that you may try cleaning your battery posts and terminals with a "post and terminal" cleaning tool.
Let us know if that works or if it is a different problem.
Good luck,
Frank