2005 Ford Focus Electrical Problem

The car runs along well then all the interior electronics goes crazy with lights flashing etc. Then it seems the engine is getting ready to die and bogs down bad then comes back. Ford said it was the alternator and replaced the expensive item. Two weeks later its back to trouble, so back to Ford. Again they said the other alternator must have been bad and replaced it again.
Now three months later it's back and worse, it does all the regular things but now when I shut it off everything is dead until I remove the positive battery cable and reconnect then there is clicking under the hood and all is well again. Any suggestions? Thank you