Harry Mason can find it in the room beyond the classroom on the basement floor of Nowhere, on top of a gurney in the same room the pliers can be found in. The screwdriver is used to unscrew the metal panel on the wall of a room on the second floor of Nowhere. Unscrewing the panel reveals the Key of Aratron hidden behind it.
Silent Hill 3
Heather Mason can find the screwdriver lying on a box in the northeastern corridor on the fifth floor of Hilltop Center, near the same area as the Gallery of Fine Arts. Heather uses the screwdriver in order to open a jammed drawer in an office room of Monica's Dance Studio. Inside the drawer, Heather will find the rope she can use to climb down the elevator shaft.
Unlike most other items, the screwdriver only appears if the puzzle difficulty level is above easy. If playing on easy, the drawer containing the rope will simply be left open.