burnttoast

Ok so I have a 2005 Mazda 3 stock I had an after market stereo In stalled about a week ago by a so called professional and yesterday when I went to start it I heard sparks coming from the stereo and smelled smoke now I have no power to my dash lights except the airbag light now the car wont even turn over clicks once when I turn the key ( which I'm almost. Positive is the electric fuel pump turning on ) I'm at a complete loss on where to turn I have so far replaced every fuse under the dash and load tested the battery Im going right now to replace the relays and fuses under the hood any helpful hints at all would be much appreciated