The stereo, clock and internal lights are not working?

I have replaced the fuses for all three, but nothing. I have also looked underneath the dash for unplugged wires but did not see anything that looked out of place. I'm baffled.

History: A few weeks ago, my 19-yr-old daughter (who is the sole driver of this vehicle) opened the driver's door and threw her keys with the remote key on the passenger seat as she helped a couple of children get in the back. At this point she heard a low beep coming from the car. It was the same beep she hears when she locks or unlocks the car, but it kept going. When she put the car in motion, the beep stopped, but it would start up again as soon as she parked it. I was at work at the time so I couldn't help her, but she had a couple of guys look at it to no avail. Although one of them reached underneath the dash to see if he could find anything wrong. Finally, I got home and fiddled with the remote key buttons until the beeping stopped. (I pressed one of them twice in succession and that's what did it.)

However, since that point, the stereo, clock, and internal lights don't work! It seems to me that there must be one wire (or wire group) that controls all three of these things, but I don't know if that's true. And if it is true, I can't find any such wire that is disconnected. My next step is to take it to a mechanic, but I would really rather fix it myself because I suspect it's a simple fix.