Check to make sure your wires aren't fried:

Disconnect everything at both ends.
Tie black to ground at one end and check for continuity at the other.
Do the same for white to ground.

 If you don't get continuity in one of these scenarios, find the broken wire by swapping what's tied together....not that it would matter. If you don't get continuity in ANY of these circuits, you'll have to replace the entire length.

Note that none of this will work if you have shorted any wires, though, you shouldn't be able to reset the breaker.