Audio Help!

i just got my sound system installed yesterday and it worked great all day yesterday. this morning i start my car and the sub was not working. i checked all of the connections and fuses, they were fine. i also see that the power light is on the amp... meaning it IS getting power. i did notice that the sub had shifted forward and the RCA wires were being tugged on. any suggestions before i go back to the shop and get raped for them to just to look at it?
~FRANKO

i hate to be captain obvious but make sure all ur wires are plugged in properly, no loose connections. Might wanna check the back of the head unit for wires that may have come off. Is it just the sub or are the tweaters not working either?