original text ：https://www.cnblogs.com/GT_Andy/archive/2010/03/16/1921836.html

1. Minimize to system tray

add to notifyIcon and contextMenuStrip

        private void Form1_Load(object sender, EventArgs e)
        {
     
            WindowState = FormWindowState.Minimized; // Minimize to system tray 
        }      
        // To minimize the 
        private void Form1_Resize(object sender, EventArgs e)
        {
    
            if (WindowState == FormWindowState.Minimized) // Minimize to system tray 
            {
    
                Visible = false;
                notifyIcon1.Visible = true;
            }
        }

1.1.notifyIcon Set up ：

1.2.NotifyIcon Double click to pop up the software

        //NotifyIcon  Double click to pop up the software  
        [System.Runtime.InteropServices.DllImport("user32.dll", EntryPoint = "GetForegroundWindow", CharSet = System.Runtime.InteropServices.CharSet.Auto, ExactSpelling = true)]
        public static extern IntPtr GetF();          // Get the handle of this form 
        [System.Runtime.InteropServices.DllImport("user32.dll", EntryPoint = "SetForegroundWindow")]
        public static extern bool SetF(IntPtr hWnd); // Set this form as the active form 
        private void notifyIcon1_MouseDoubleClick(object sender, MouseEventArgs e)
        {
    
            Visible = true;
            WindowState = FormWindowState.Normal;
            Show(); 
            if (this.Handle != GetF()) // If this window does not get focus 
                SetF(this.Handle); // Set this window to get focus 
        }

1.3.contextMenuStrip Set up ：

       // Right click the small icon menu  -  sign out 
        private void  sign out ToolStripMenuItem_Click(object sender, EventArgs e)
        {
    
            Close();
        }

2. Boot up

// Boot up 
        private void checkBoxReboot_CheckedChanged(object sender, EventArgs e)
        {
    
            string R_startPath = Application.ExecutablePath;
            if (checkBoxReboot.Checked == true)
            {
    
                RegistryKey R_local = Registry.LocalMachine;
                RegistryKey R_run = R_local.CreateSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Run");
                R_run.SetValue("BirthdayTipF", R_startPath);
                R_run.Close();
                R_local.Close();
            }
            else
            {
    
                try
                {
    
                    RegistryKey R_local = Registry.LocalMachine;
                    RegistryKey R_run = R_local.CreateSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Run");
                    R_run.DeleteValue("BirthdayTipF", false);
                    R_run.Close();
                    R_local.Close();
                }
                catch (Exception ex)
                {
    
                    MessageBox.Show(" You need administrator privileges to modify ", " Tips ", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    throw;
                }

            }
        }