Private Sub Worksheet_Change(ByVal Target As Range) 
    Dim blnValue As Boolean 
    Dim shpCB As Shape 
    If Target.Count = 1 Then 
        If Not Intersect(Target, Range("C4,C6")) Is Nothing Then 
            blnValue = WorksheetFunction.CountA(Range("C4,C6")) = 2 
            For Each shpCB In ActiveSheet.Shapes 
                If shpCB.Name Like "Check*" Then 
                    shpCB.ControlFormat.Value = blnValue * -1 
                End If 
            Next shpCB 
        End If 
    End If 
End Sub