The small bedroom in my house has terrribly creaking floorboards.

Hi Clare When screwing the boards down to stop them squeaking you have to use the right screws to pull the boards tight to the joist you need a screw with at least a 15 to 20mm smooth shank between the head and the threads to allow the board to pull completely down if you use a screw with threads up to the head it will just hold the board in the same position as before allowing it to move when walked on so remove all the screws and start again the other way would be to drill a clearance hole in the board slightly bigger than the thread but this needs to be accurate in hole size and the depth needs to be right. I hope this cures the problem if so click the like button Thanks Kelvin

Get a chippy to have a look, it could be numerous things causing it. As said above plus, the floor maybe rubing against conduit in the wall, pipes etc. Sometimes it can be a loose/weak joist that is moving as you walk across it.

You've got a lot of fair comments particularly about the type of screws but could I just say be careful putting screws in there are often pipe runs just under the floor boards in certain cases. What's caused it? Floor joists always shrink that won't help and the boards are probably nailed originally. Good Luck

If you can get them up, apply a small bead of sikaflex along top of joists then screw back down, although plenty of screws should have cured it.

Clare.... going on the additional info,i would try Brians suggestion and apply some sikaflex along joists then screw boards back down. If that doesn't work,then i don't know........maybe look at replacing them with proper timber floorboards,unless any joiners/floorers read your post and come up with alternative suggestions. Chipboard flooring is notorious for the problem you have. Carl.