using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace WindowsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Rectangle screenRect = Screen.PrimaryScreen.WorkingArea;
            Bitmap dumpBitmap = new Bitmap(screenRect.Width, screenRect.Height);

            using (Graphics targetGraphics = Graphics.FromImage(dumpBitmap))
            {
                targetGraphics.CopyFromScreen(0, 0, 0, 0, new Size(dumpBitmap.Width, dumpBitmap.Height));
            }

            // Save ti dist
            dumpBitmap.Save(@"C:/test.png", dumpBitmap.RawFormat);

            //show in picture box
            //this.pictureBox1.BackgroundImage = dumpBitmap;
            //this.pictureBox1.BackgroundImageLayout = ImageLayout.Stretch;
        }


    }
}


แถมอีกนิด 

Run the application at Windows startup

The full path to it is HKEY_CURRENT_USER\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run or if you want the setting for all the users of the

using Microsoft.Win32;

// The path to the key where Windows looks for startup applications

RegistryKey rkApp = Registry.CurrentUser.OpenSubKey("SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run", true);

// Add the value in the registry so that the application runs at startup

rkApp.SetValue("MyApp", Application.ExecutablePath.ToString());

// Remove the value from the registry so that the application doesn't start

rkApp.DeleteValue("MyApp", false);

// Check to see the current state (running at startup or not)

if (rkApp.GetValue("MyApp") == null)

{

   // The value doesn't exist, the application is not set to run at startup

   chkRun.Checked = false;

}

else

{

   // The value exists, the application is set to run at startup

   chkRun.Checked = true;

}