A friend of mine who is totally unpractical and has no diy skills at all got fed up with the creaking floor boards in their bedroom so he went out and bought a cordless drill and a box of screws!!!! and just went around and randomly screwed the floor boards down a day or so later they noticed water coming from the ceiling so he got a plumber mate around to take a look and found on a section of floor indicating there was pipes there he had screwed 3 screws through various pipes, but he did stop the creaking!!!