head unit problem

[hjs]

sorry, im really new to this and couldnt find a thread that helped, just got myself a punto mk2 i think, and it already had an after market head unit in it. all speakers worked perfectly with this in. i pulled that one out and put my own in, a simple unplug of that one and plug in my own. or so i thought. now for some reason the front speakers wont work. the rear speakers are fine and work perfectly. is there something wrong with my head unit? it worked fine in my last car. or is it something to do with the wiring?

if anyone can help it would be greatly appreciated as iv spent most of the day fiddling about with it and its making me so mad! :bang: