Battery dies

Hello All

I have a 91 Marquis and the battery is only charging a few amps. I have replaced the battery, alternator , regulator, checked all connections and wires and have disconnected the deicer. This all started when my windshield deicer stopped working. I have had it computer diagnosed and got no answer.
:screwy: Any help before I go INSANE?????:screwy:

when replacing the battery are u buying a used one or one for cheap like from a junk yard i got one from a junkyard and it didnt work that happed 3 times till i found one that actually worked