Crush a 1 lb. bag or oreos, reserving 1/2 cup crumbs. Spread remaining crumbs evenly in 13X9 pan. Melt 2 sticks of butter or margarine and pour evenly over crumbs. Chill at least 1 hour.
In mixing bowl, combine 2 8 oz pkg softened cream cheese, 1 cup powdered sugar and 1/2 of a medium sized cool whip. Spread evenly over chilled crust. Chill at least 1 hour.
Make up 1 large instant Jello chocolate pudding using 2 cups of milk instead of 3. Spread evenly over previous layer and chill at least 1 hour.
Spread other half of cool whip over pudding layer. Sprinkle with reserved crumbs and refrigerate till ready to serve, but at least 1 hour.