If you do not mind the form being shown modal, then this would work:
Dim f2 As New Form2
f2.StartPosition = FormStartPosition.CenterParent
f2.ShowDialog()
Else:
Dim f2 As New Form2
f2.StartPosition = FormStartPosition.Manual
f2.Location = New Point(Me.Location.X + Me.Width \ 2 - f2.Width \ 2, Me.Location.Y + Me.Height \ 2 - f2.Height \ 2)
f2.Show()
Where "Me" is the form that shows "f2".