One of two ways, 1 remove all your trim around windows and doors including baseboards and start ripping it out. Once removed, remove all nails and screws from studs and your ready to start all over again. 2- remove all trim and base as above and depending on the reason for removal, if you want to replace with new drywall you may leave the existing drywall and laminate with new right over the existing with panel adhesive and apply screw and finish as per norm.
