I have no power on one circuit from the breaker box... I have replaced the breaker, all outlets, switches, and light receptacles on the circuit... all wire junctions seem to be secure... any other ideas??

Start by testing for power right off the breaker. If you detect 120 volts move down the circuit to the first receptacle and test again. Somewhere at or after the connection to the breaker you have dropped a leg, hot or neutral