Well, if your working in a newer house that has 3/4" tounge and groove plywood subfloor remove everything to that, screw down areas that may be loose or have bounce, lay a good foam underlayment and assemble the laminate flooring.
If you are in an older home that has an original subfloor made up of tounge and groove boards or just individual boards nailed at a 45 degree angle to the walls stop removing to there unless that layer is rotted then replace bad boards and lay good 7/16 plywood sheets (3/4" t&g is better off you can put that down but you might create lips between rooms or your door casings may need to be adjusted) down perpendicular to the floor joist. Glue with liquid nails and screw the floor down ensuring you sink screws into the floor joists. Add extra screws along seams to reduce the seams from warping. Once that is finished, lay a good underlayment and assemble your floor. Hope this helps, good luck
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