Where is the Main method in a forms application?

When you create windows form project ( A Gui one), it has a main loop--In fact it requires one. By default, it's in program.cs and it kicks off your form:

static class Program
{
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new Form1());
    }
}

What you probably want though is the Form constructor. This is in the code behind of the Form (by default Form1.cs) and will look like this:

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();     
    }          
}

A WinForm application starts from main

static void Main()
{
    Application.Run(new Form1());
}

Whatever you want to do in main you can do it here