Q: After installing 2 new sub woofers in the vehicle, there was a pop and now the engine will not start.

It all started back around march when I had to change my alternator and the relay in the fuse/relay center, ran fine until may when I tried charging my ac compressor, it wouldn't start after that and wren it did it made a horrible noise so I ended up changing the whole ac unit along with the belt. All was good until it started not wanting to start, only when it wanted to would it start. So I changed the fuel pump and the filter. It ran fine for a while and then bout a month later it started doing the same thing. It will only turn over and not fire up. So I changed the spark plugs, the plug wires, distributor cap, rotor and still nothing. I then changed the ignition control module and it fired up. Upon hooking up my 2 12' subs when connecting the positive lead to the battery I heard a pop in the back of the Yukon and when I tried starting it t would not start. (I was looking around and found a little black fuse type thing just laying there out in the open, have more of ? No room here

My car has 200000 miles.
My car has an automatic transmission.