Both the first and second floors squeak when you walk across them. I tried to fix the problem using a product called Squeeeek No More (I think). You use a special drill bit to find the joist and then you place a 3-legged metal piece on the area and drill in a special screw and then snap off the head of the screw. I drilled many holes, some missing the joist, and put in many screws when I thought I was on the joist. I felt like I was chasing the squeak across the room. I then hired a handy man who took up the carpeting on the first floor and put screws through the padding and plywood into the joists. Since the first floor bathroom and kitchen have hard wood floors, he went into the crawl-space and put screws from underneath into the floor to draw it down. When he left the first floor was pretty quiet, but a few months later the noise has returned both on the carpet and hard wood areas. As far as me finding and correcting the problem on the second floor, I have made many holes, some not on the joists, and put in many screws when I thought I hit the joists, but still I have squeaks everywhere. My wife is afraid that I am weakening the floors with all the drilling.
Anything suggestions would be greatly appreciated.