No power in an electrical outlet?

I have an outlet in my house with no power. I just had the walls open and there was no problem with the wire from the box to the top plate . (50 yr old house) All circuit breakers are fine, I tried using an AC tester to the hot leads with no luck. I want to know where in the house the feed comes from to that outlet (it's on a completely different circuit then the rest of the room.) Can I use a tone generator to find out where the feed comes from? if not, what type of tool would help me trace where the 14-2 wire comes in from to troubleshoot lack of power.