private Point origPosition;

        private void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            origPosition = Cursor.Position;

            Cursor.Position = new Point(
                (int)(Screen.PrimaryScreen.WorkingArea.Width / 2.0),
                (int)(Screen.PrimaryScreen.WorkingArea.Height / 2.0));
        }

        private void Form1_MouseUp(object sender, MouseEventArgs e)
        {
            Cursor.Position = origPosition;
        }