Installed new alternator and battery today. Hooked everything up the way it came off, went to hook the neg battery terminal up and as soon as it made contact with the battery it arched badly and I heard a loud "pop" sound over near the passenger side of the engine bay. Usually once the neg battery terminal is hooked up you hear the fuel pump whine and then your good to go. Now after this happened nothing works at all except the parking lights from the top steering wheel switch. I put the key in the ignition... nothing, no fuel pump priming sound, wont crank, no door locks, key fob don't work, no lights, no radio, no headlights... absolutely nothing works. Checked all the fuses and they are good, relays I am not sure how to check them. Unplugged the battery and plugged it back up and there's still nothing.
What has happened?