Instrument and tail lights

Here's my situation. I've checked all bulbs, and all fuses literally. My instrument and tail lights went out on me and will not come on. I really don't understand what could be wrong. Please help. Could it be a wiring problem, or a short or possibly a computer problem. What happend, I was changing out my radio and I heard a pop, I suspect a wire touched a metal spot. I just don't know what else it could be. Please help me out.