The extra wires could be for a electric antenna , also it could be an aux 12 volt output source.
What I'd try is switching the wires around connect the stereos rear output wires to the front speakers and see if they work then and if they don't work it could be that the front speakers are blown but check the plug in connectors on the front speakers too.Also make sure that the stereos fader switch is adjusted properly before switching any wires around.
Hope that helps and best of luck.By the way the way I have installed systems is to use wires with alligator clips on both ends then I wire the system up via the alligator clip jumpers and test the system before wiring anything up directly.Some of the door stores carry these alligator clips and all I do is get some wire about 14 gage and connect up the alligator clips to wires about a ft long each.Also you can buy them pre-made at radio shack stores.