I have some floorboards that are really creaky and have taken up the carpet to replace it. I have read previous posts which suggest screwing them down where they are loose and to avoid screwing into pipes and electrical cables - but would anyone be able to tell me how I can avoid them? How would I know where they are? I have screwed down the boards in the sitting room years ago but never thought of cables etc. - just happily screwed away, but now I'm not so confident. Also are screws better than nails for the job? Thanks in advance for any help.