cruise control and stereo inoperative, and 4 chirps from alarm
 

2002 A4, 3.0l, quattro, manual transmission:
Driving around last Saturday. Stereo was on and working in the morning.
On the way home my wife got a call so turned stereo off. On the freeway I try to turn in cruise control, it doesn't work. When I get home to garage I turn off car and notice that the stereo back lighting is on and really bright (display is blank). I hit the power button and no response. So check fuses, I pull stereo fuse which is fine, and causes the back light to turn off. Place fuse back and the stereo stays dark and does not turn on.
Next day, start the car and right after starting the alarm chirps 4 times. It has been doing that every morning start since Saturday.
Has anybody had any one of these problems? If so what was the fix? I'm not entirely sure that are all related to a certain electrical system/component or just all coincedence.

I'm not sure about the other parts but I have read the four chirping means the backup battery for the alarm is going bad.

Thanks I will search for that. I just need to figure out how to troubleshoot the radio and cruise control.