no power??

damn...i hate my audio system...
i have been fixing it for 4 days !!!
help me out plz !!

ok.. i was reconnecting my wires from the deck....
i forgot to disconnect my main battery's negative....

when i was reconnecting the power wire from the car, it touches the metal of my car and made a spark, then.. i removed my main battery's negative side, after i reconnected everything, my deck won't start !!! damnit !!!!! how come??
I thought i blew the fuse of the car audio power wire, then i checked at the fuses panel, that fuse is alright ! nothing is wrong..
then i used a meter to measure how many volts the batter wire has, it only has like 5 volts... is this normal?? how come?? can somebody help plz??