In Silent Hill, the screwdriver is an item that Harry Mason can pick up and use. It's found in the room beyond the classroom on the basement floor of Nowhere, and is lying 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 action difficulty level is above easy. If playing on easy, the drawer containing the rope will simply be left open.
Silent Hill: Origins
The screwdriver is a common object that Travis Grady can pick up and use as a weapon. It will break after some use, just like all other melee weapons in the game. The screwdriver, like the scalpel, is very short range but fast, allowing Travis to finish off his enemy with swift, jarring motions before they have a chance to strike. Once an enemy has fallen, Travis will stab it with the melee weapon.