I'm writing C# code for a windows form calculator. I've gotten it all written and ready to run but I'm getting 4 errors: using System; using...

I'm writing C# code for a windows form calculator. I've gotten it all written and ready to run but I'm getting 4 errors:

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

using System.Globalization;

namespace Calculator

{

   public partial class Form1 : Form

   {

I have error in Data, Drawing, Forms, and Form which I pointed out in BOLD FACE!

Data, Drawing, and Forms says namespace doesn't exist

Form could not be found.

I can't for the life of me figure out what the resolve is.