Preheat the oven to 425 degrees. Let the pie crust shell thaw for 10-15 minutes on the counter; prick the sides and bottom all over with a fork. Bake the pie crust on the bottom oven rack for 10-12 minutes or until nicely golden brown; cool.
Meanwhile, combine the sugar, cornstarch, and water in a saucepan over medium heat; cook the mixture until nicely thickened, whisking often.
Remove from the heat and whisk in the box of gelatin until it is completely dissolved; allow this mixture to cool slightly.
Slice the strawberries lengthwise into slices; place them into the cooled and baked pie crust.
Pour the slightly cooled (it can still be a bit warm) gelatin mixture over the sliced strawberries in the baked and cooled pie crust.
Refrigerate the pie until the filling is set and the pie is fully chilled throughout, 4-6 hours.
Slice the pie into 6 pieces and top with whipped topping; serve at once.