Outside flood light problem
It sounds like you have a fault between the switch and the fixture. Search for nearby junction boxes to see if there's a bad connection somewhere. Do what you can to trace the line, especially if it goes up to an attic or down to an exposed basement. You should also check if the problem is a faulty hot (no current from the hot to a known good ground) or a fault neutral (no continuity between the neutral and a known good ground) to narrow your search. If you can't find the fault, you'll need to run a new line from the switch to the fixture.