Car Stereo

In our 89 escort we tried to wire up a stereo with the factory wires attempted to put it in the slot and then there was no sound just light no display or anything. we tried a different stereo and there was nothing at all not even light. so i was wondering if we fried the entire wiring system? another thing when we touch the constant power wire to the accessory power wire the lights in the car come on and the digital clock. any ideas there? the fuse is a blue 15 and its not blown, could it be faulty anyway?

Theres fuses to prevent doing serious damage, and now they need to be replaced. go to the fuse box inside your car and there should be a blown red 10amp fuse to replace(but check all to be sure) the head unit should have a fuse on the back of it also check that to make sure its not blown also.