Sounds like somewhere there's a break in your circuit. If you can get a hold of an ohmeter (resistance measurer) you can use it to check parts of the circuit to narrow down where the break is (low resistance = OK, high resistance = you found it!).
Instead of an ohmeter, you can rig up your own checker, using the power supply you already have (which sounds like it works).
Run a couple of wires from it to a light bulb, buzzer, or anything that lets you know it is getting power. Then put parts of your circuit into the mix to see if they allow the light bulb or whatever to get power.