private void Form_Giris_Load(object sender, EventArgs e)
        {   
            if (System.Diagnostics.Process.GetProcessesByName(System.IO.Path.GetFileNameWithoutExtension(System.Reflection.Assembly.GetEntryAssembly().Location)).Count() > 1)
            {
                MessageBox.Show("Program zaten açık....");
                System.Diagnostics.Process.GetCurrentProcess().Kill();
            }
               
        }