Well if you want the other options to appear, but be disabled then I don't think that is easy task because of the nature of the control. Look at this: Hide item in combobox
Otherwise I think you can do it this way:
Select Case ComboBox1.SelectedItem
Case "Michigan"
ComboBox2.Items.Clear()
ComboBox2.Text = ""
ComboBox2.Items.Add("Detroit")
ComboBox2.Items.Add("Ann Arbor")
Case "Ohio"
ComboBox2.Items.Clear()
ComboBox2.Text = ""
ComboBox2.Items.Add("Cleveland")
ComboBox2.Items.Add("Dayton")
End Select With that, it would only be necessary to put only the following in the Form1_Load event:
Me.ComboBox1.Items.Add("Michigan")
Me.ComboBox1.Items.Add("Ohio")