More in Floors
Pry one of the old boards with a pry bar and take the piece to the lumberyard to find new hardwood flooring planks that match in size and wood type.
Carefully remove damaged floor boards down to the solid material underneath. Remove the floor in a staggered pattern (and be sure to install in a staggered pattern to hide the seams).
Prepare subfloor by removing any nails or debris left behind that could interfere with the new flooring.
Use staples to secure a layer of rosen paper to the floor to provide a "friction layer" that will minimize squeaks.
Cut the new floor boards at random lengths to re-create the staggered pattern of the original floor. Try to match the original lengths to better conceal the repair.
Use a cordless nail gun to shoot nails into the new pieces of flooring.
Note: One of the advantages of a nail gun is its ability to drive nails deeper into the wood, recessing the heads and making them more easily covered by wood putty or filler.