My flooring--second story, carpeted--squeaks. I tried the scored screws solution answered in this question. I covered the entire room and adjacent hallway with scored screws on all the joists, every 6 inches, per the instructions. After the fix, the squeak still exists, but walking around the room/hallway, the squeak now seems to be more localized--specifically, the sound emanates from the edge where the wall meets the floor. I can walk in the middle or the side of the room and the sound still comes from the edge.
How do I fix (or verify) the cause the squeak? I'm happy to provide more info; but I'm not even sure how to proceed to gather more information.