did you have it long? Is this you second unit with the same harness?

check the harness and make sure no +12vlt wires are exposed. wires like illumination,power antenna that dont get capped off can sometime ground them selves and cause some damage.

For the sound to stop it seems like you having a speaker grounded out. Check to make sure non of the wires are the touching metal they are being screwed to.

its not common but sometimes the speakers when they blow they gound out and cause the others to stop playing. We found that to be the case when installing some beyma 6.5's once. speaker blew and grounded the VC.