Lock Excel 2013 cells based on other cell input

Question

I have a worksheet with many different columns for input. The columns in question are D, H, and I. D and H are drop downs. I is any text input. I am trying to put together a VBA script so that if a selection is made in D2 then that will lock H2 and I2. If a selection is made in H2 then that will lock D2 and I2. If text is entered in I2 then that will lock D2 and H2. Lastly, this will need to be done for the entire column of D, H, and I so that each cell in those columns have the same property ie D16 and H16 will lock if I16 is filled and so on and so forth.

If this can be implemented by formulas as well I do not mind.

  `  Private Sub Worksheet_Change(ByVal Target As Cells)
            If ActiveSheet.Cells(2, 4).Text = True Then 
'This is what I don't understand. I don't know what to set the text to. I'm trying to say if there's anything in the cell Then do the following...
                ActiveSheet.Cells(2, 8).Locked = True
                ActiveSheet.Cells(2, 9).Locked = True
            Else
                ActiveSheet.Cells(2, 8).Text = True Then
                ActiveSheet.Cells(2, 4).Locked = True
                ActiveSheet.Cells(2, 9).Locked = True
            Else
                ActiveSheet.Cells(2, 9).Text = True Then
                ActiveSheet.Cells(2, 4).Locked = True
                ActiveSheet.Cells(2, 8).Locked = True
            End If
    End Sub`

Answer 1

Try this code, but bear in mind locking cells as no affect unless the worksheet is protected. Also note that ByVal Target as Range is the correct syntax for the Worksheet_Change argument (not ByVal Target as Cells ).

Private Sub Worksheet_Change(ByVal Target As Range)

If Len(Target) Then

    Select Case Target.Column

        Case Is = 4

            Me.Unprotect "pwd"
            Cells(Target.Row, 8).Locked = True
            Cells(Target.Row, 9).Locked = True
            Me.Protect "pwd"

        Case Is = 8

            Me.Unprotect "pwd"
            Cells(Target.Row, 4).Locked = True
            Cells(Target.Row, 9).Locked = True
            Me.Protect "pwd"

        Case Is = 9

            Me.Unprotect "pwd"
            Cells(Target.Row, 4).Locked = True
            Cells(Target.Row, 8).Locked = True
            Me.Protect "pwd"

    End Select

End If

End Sub