I believe you have two issues here.
have you checked the power at the headlamp bulbs?? If you do, then apparently the bulb is bad. if you do not have power, you have to trace the positive cable until you get to a point where there is power, it might be a connector, a relay, or a broken cable.
the starting issue might have to do with the headlight. there are a few threads on bikes not starting. find one that has a trouble shooting process and dig in.