I have hardbored floors that are sat on a foam like material that is sat on another hardboard rather like a sandwich they squeak and groan everytime you walk over them

there does not seem to be any joists that it is sat on and i am a first floor flat so presuambly the guy below i will be resting on his joists has any one come across this type of constructon before and what can be done to remedy it

The laminate flooring that rests on the foam layer will usually never squeak or make noisy. It may be the floor that the foam is sitting on was not fastened well before the laminate was installed. If the first layer of hardwood is what is squeaking you will need to remove the laminate, and foam to address the problem.You could find loose hardwood boards, or the sub-floor may be loose under the hardwood floor, or both may be loose and need to be fastened better with 6d or 8d finish nails. 6 or 8 penny finish nails could be used depending on what is loose.
Do not try to fasten through the laminate floor since there is a foam layer that is there to support the laminate flooring.

The floor dried up. Or the floor is uneven. Call a craftsman, he will tell you the exact cause.