2003 Honda Civic problem?

My girlfriends car wouldn't start , no power so tried to boost,no luck.Took battery to garage to test battery ok.I put back in car and nothing ,no lights ,clock, no start ,except the hazard lights work.so i am assuming it's in the wiring .So before i take it to garage is there any way to check myself,like what look for or where to start.Anything would be appreciated !Thanks