Gary,

You need to convert the client coordinates to screen coordinates. Something like this should position your form. Notice that you must set the forms StartPosition property.

private void button1_Click(object sender, EventArgs e)
{
   Rectangle rectPosition;          
   Form1 formTest = new Form1();

   formTest.StartPosition = FormStartPosition.Manual;

   formTest.Left = button1.RectangleToScreen(rectPosition).Left;
   formTest.Top = button1.RectangleToScreen(rectPosition).Top + button1.Height;

   formTest.Show();
}

Regards
Neil