Prepare crust: Combine graham cracker crumbs, butter or margarine, and sugar; mix well. Press crumbs evenly in pan. Bake in 325 oven until crust smells toasted, about 8 minutes. Let cool; if made ahead, cover and let stand at room temperature up to overnight.

Pour water into small pan; sprinkle gelatin over water and let stand until softened, about 5 minutes. Place over low heat and stir until gelatin is dissolved (40 secs in microwave).

Puree 1 cup berries in blender or food processor. In bowl, beat together pureed berries, sugar, yogurt, and liquid gelatin mixture. Stir in remaining sliced strawberries. Cover and chill 25-30 minutes until mixture begins to set up.

Spoon strawberry mixture into crust and refrigerate until filling is firm to the touch, at least 4 hours; cover to store as long as overnight