Private Sub cmdOK_Click()
  Dim rngSelect As Range
  Dim rngCell   As Range
  Dim lngColor  As Long

  On Error Resume Next
  Set rngSelect = Range(RefEdit1.Value)
  If Err.Number = 0 Then
    Select Case True
      Case optColor1.Value: lngColor = RGB(255, 0, 0)
      Case optColor2.Value: lngColor = RGB(255, 255, 0)
      Case optColor3.Value: lngColor = RGB(0, 0, 255)
      Case Else
    End Select

    For Each rngCell In rngSelect.Rows
      If rngCell.Row Mod 2 = 0 Then
        rngCell.Interior.Color = lngColor
      End If
    Next rngCell
  Else
    MsgBox "'" & RefEdit1.Value & "'" & _
          " ist kein gültiger Zellbezug!"
    RefEdit1.SetFocus
  End If
  On Error GoTo 0
End Sub