Since your car is OBD2 I would take it to Honda and have them hook up a code reader to see.

But both your problems seem to be a grounding problem or a short in the car somewhere (heck they might be related). I'm gonna guess the battery first. Check to make sure the wires to the battery and coming from the battery are secure. I had a problem like this with my 00 Civic Si but I kept blowing my amp.

Next check the speaker wires. Ground and positive.

The last thing I can think of is the OEM CD player might be bad. Remember the code for each player is hard wired, and is also responsible for the door locks. If the CD player was dropped it could have cause internal damage. See if you can find someone to swap out headunits.