Put on work gloves. Cut a slit in the existing carpet with a utility knife. Work the knife into the slit to cut it wide enough to reach your hand in. Holding the carpet with one hand, begin cutting the carpet and padding with the other.
Cut away pieces of the carpet and padding, and place them into a large trash bag as you work. Cutting up the carpet into small manageable pieces is easier than trying to lift and carry sizable pieces. Roll up and secure larger pieces with duct or shipping tape to make them easier to carry and discard.
Put on eye protection. Starting anywhere along the borders of the room, work the pry bar under a nail or staple on the tack strip.
Tap the pry bar with a hammer to loosen the nail and then push down on the pry bar to release the nail. As you pry up the nails, pieces of the tack strip will break off with it. Discard them in a trash bag as you work to avoid accidentally stepping on them.
Use needle nose pliers to remove nails or staples that don't pry up with the crowbar.
Apply mastic remover as directed by the manufacturer if the carpet was glued down. Dark-colored adhesive may require mineral spirits or a commercial adhesive remover. Chip yellow-colored adhesive with a putty knife.
Use a plastic putty knife to scrape away the adhesive. Plastic putty knives will do less damage to the floor than metal ones.
Sweep away nails, tacks and carpet pieces and then mop the floor with soapy water, rinse and allow to dry.