I removed the carpet in a second floor bedroom to put down pergo flooring. The 1987 particleboard underlayment squeaks at the joints between two pieces when I step on it in a few places. This is between the floor joists, and the particle board sags a little at its edge and rubs against the adjacent piece creating the squeak. I don't have access to the bottom of the floor to install a bridge. How do I stop the squeaking before I lay the flooring?