what to you mean by the left one? there should only be headphones and Mic. it sounds like you have the front panel hooked up wrong
the panel showing front is located at middle of 3 rear jacks. it used to play earlier when connected there till a few weeks earlier when it automatically stoppped playing sounds.
when i use realtek hd manager, turn to quadraphonic and connect my speaker to headphone jack, it plays but the sound isnt recognisable. what the hell is wrong?