[particlewave]

The clack is the solenoid/bendix being actuated. That same action makes a contact within the starter to tell it to start spinning.

If the motor coils are toast, you can get the symptoms you describe. Did you fully test the starter to make sure that it is activating the solenoid and spinning the motor?

Edit: didn't your engine die while driving before the symptoms started? That would point to something aside from the starter.