Combine crushed pretzels, melted margarine and 3 tbsp sugar. Press into 9 x 13 pan. Bake at 350 degrees for 10 minutes and cool.
Cream the cream cheese, powdered sugar and cool whip. Spread on pretzel crust and refrigerate. Mix Jell-O, water (hot and cold) and strawberries. Let Jell-O thicken and pour over cream cheese layer. Refrigerate. Cut and serve.