Stir in powdered sugar, milk, and salt in microwaveable dish. Add margarine, and microwave on high for 1 mintue. Repeat process for the next 11 1/2 mintues or longer. You have to get the mixture bubbling Stir in chocolate chips, vanilla, and pecans untill melted. Spoon into a 9 by 9 inch pan. Refrigerate 2 hours. Cut into pieces