Combined crushed cookies and melted margarine and press into a 9x13 inch dish. Chill 1 hour in refrigerator.
In a saucepan over medium heat, combine confectioners' sugar, evaporated milk, chocolate chips and 1/2 cup margarine. Bring to a boil, stirring constantly, and boil 8 minutes. Remove from heat and stir in vanilla. Set aside to cool.
Slice vanilla ice cream into 3/4 inch slices, and place them in a single layer over the chilled crust. Smooth the seams. Sprinkle the peanuts over the ice cream. Top with the cooled chocolate sauce. Cover and freeze 8 hours or overnight.