Try sprinkling some baby powder (talc) on the squeaky spots and see what happens. Just sweep into the "cracks" and then sweep up excess. May have to reapply every once in a while.
By
11/09/2009
Here is one answer from a handyman. There is a bit of space under the Pergo on an uneven floor, and the Pergo is moving a bit when you walk on it. Have the installers come back and insert thin paper or cardboard to prevent the flexing. If the wood floor is indeed squeaking, you will have to nail.