aide concernant un problème de "CheckBox"

Private Sub CommandButton1_Click()
With Sheets("Feuil1")
  .[B3] = -CheckBox1
  .[B4] = -CheckBox2
  .[B5] = -CheckBox3
  .[B6] = -CheckBox4
  If Application.Sum(.[B3:B6]) = 0 Then MsgBox "Aïe aïe aïe..."
End With
End Sub

Private Sub CommandButton1_Click()
  For n = 1 To 4
    If Not Me("CheckBox" & n) Then
      MsgBox "case(s) à contrôler !", vbInformation, "Alerte..."
      Exit Sub
    End If
  Next
  For n = 1 To 4: Cells(n + 2, 2) = n:  Next 'pour un contrôle éventuel
End Sub

Private Sub CommandButton1_Click()
If CheckBox1 + CheckBox2 + CheckBox3 + CheckBox4 = 0 Then
  MsgBox "Aïe aïe aïe..."
  Exit Sub
End If
With Sheets("Feuil1")
  .[B3] = -CheckBox1
  .[B4] = -2 * CheckBox2
  .[B5] = -3 * CheckBox3
  .[B6] = -4 * CheckBox4
End With
End Sub