private void ShutDownComputer(object sender, EventArgs e)
        {
            try
            {
                computerName = dataGridView1.SelectedCells[1].Value.ToString();
                computerBl   = new ComputerBL();
                computerBl.ShutDownComputer(computerName);
            }

            catch (ArgumentOutOfRangeException)
            {
                MessageBox.Show("Lütfen tüm satırı seçiniz", "Uyarı", MessageBoxButtons.OK, MessageBoxIcon.Warning);
            }
        }