Open the door.
Tighten all the screws holding the top door hinge to the door frame by turning them clockwise with a Phillips screwdriver.
Reopen the door if it still drags on the floor.
Remove two of the top hinge screws by turning them counterclockwise with the Phillips screwdriver. Run one 3-inch wood screw through both open hinge holes. Close the door. Tap the hinge lightly away from the door with a hammer if the bottom of the door drags across the flooring.
Open the door if the door still drags across the floor. Stack cardboard under the door until the upper hinge does not hold weight.
Remove all screws from the top hinge with the Phillips screwdriver. Pull the hinge from the door and door frame.
Cut 1/16-inch of wood from the hinge recess by placing the beveled side of a wood chisel flat against the door frame. Tap the back of the chisel with a hammer. Ensure all material is removed from the recess. Reinstall the hinge. Close the non-dragging door.