If you have timber floorboards and they are old, they have a tendency to squeak and creak when walked on.
There is a very easy solution to this as long as there is no structural damage to the boards. All you need to do is sprinkle some bicarb soda or baby powder on the offending board and brush the powder into the cracks between the boards. Use a small paint brush to get as much powder into the gap as you can. Once done sweep up the excess and you should be able to walk about without the boards creaking.