Originally Posted by inspectorD
Unfortunately you need a good substructure underneath. There is no way to fix it without removal of the entire floor material.
If it is lock together floor, take it apart and start fixing the underneath as best you can.
Call a professional first to see your options.
I have to agree, unfortunately. You need to fix the subfloor or deal with the problem. You can find a professional at the link in my signature. Search by your zip code, then call around and see if anyone can fix the subfloor while salvaging the boards.