how about :
Me.Top = 0
Me.Left = (Screen.Width - Me.Width)
Sadly, it may not really in the top right corner coz the MDI form scroll bar showed automatically. You may need to put a number to adjust its position so the code will look like :
Me.Top = 0
Me.Left = (Screen.Width - Me.Width) - x
where x could be 100, 200...