Thanks for all of the suggestions and advice. I had someone come over with a continuity tester, and we were able to pinpoint the problem to a wall switch in a small bedroom I painted 8 months ago. When I painted, I replaced the wall swich, and at least thought I did a good job making all the connections! Didn't find it before because the light fixture connected to the switch was working fine. The switch used to control a nearby outlet, but I cut the lead from the switch to the outlet so that the outlet would always be live, and ran new wire from the switch to a new ceing fan. Just had to cut, strip, and wirenut two black wires in the box. All is well. We did determine that a dehumidifier I have in the basement is on the same circuit. Haven't blown the circuit yet, but it places enough of a draw on the circuit that a lot of the lights in the house flicker when it kicks on. I had him show me how to install a new circuit while he was there, so that will probably be the next project, although I may wait till Spring when I finish half the basement and run new wires/circuits for lights and receptacles.
Again, thanks for all the help! I will continue to read, post, and respond to posts on this great board.