Battery problems. First the radio stops working, then a few days later the car will not start.

possible lose connection to battery or ground on the body.Grab and twist every ground wire you see .tight and clean oxydaition.

check the negative wire from the battery to the body (not good ground ) clean

Sounds like someone shorted the wires...you need to look into the entire butcher job and see what wires were touched. Disconnect everything the butcher did and then see if your battery is still drainning power.

Check all fuses ,wiring anywhere short or check alternatour

Check the anti-theft module and relay

It may be a computer board problem. The board sometimes cracks causing intermitent random faults.

sounds like you need a new alternator.the battery light is triggered by the diode trio in the alternator. if the light comes on.99 times out of a 100 you need to have your alternator replaced.have your charging system checked first. most parts stores check them for free.with the engine running it should be around 14.5 volts.

If the problem occurs after the car has been driven long enough to reach normal operating temperature, the problem is the starter. If the 'no crank' occurs cold, retest the battery.

Sometime the computer in car will shut down a circuit when it sees a problem even if it only occure once. You can try to disconnect the battery for at least 2 min so all sys power off (some have capacitors that mantaine a charge for short time). If a battery disconnect does not clear problem you have go to dealer and have them to clear codes and reset you modules and your preferences

If the car is dead, it should not make a sound, this is normal for dead things. Get a live one.