Escape the Mansion Level 76 Walkthrough:
Pick up the ring above the door and place it at the end of the rope.
Drag the ring + rope downwards to the small hook next to the door and let go.
Pick up the screwdriver and key.
Use the screwdriver on the picture of the keyhole repeatedly until it falls, then use the key on the real keyhole.
Proceed to the next Escape the Mansion level!