It sounds like you have a bad thermostat or a shorted stat wire if the condensing unit keeps running after the call for cooling is satisfied. Or your contactor is welded shut. But your out side unit running with out the furnace fan running is one of the major ways to damage a compressor. It won't boil off the liquid refrigerant without the indoor fan going, then it sends liquid back to the compressor and tries to compress a liquid( which can't be compressed) and Bam broken internals, or it will wash the bearings and cussed a short. It's known as slugging the compressor.