How about like this.

\\\
Private Sub Form_Paint(ByVal sender As Object, ByVal e As PaintEventArgs) _
                                                      Handles MyBase.Paint
 Dim MyString As String = "1-2-3-4-5"
 If CheckBox1.Checked Then
   Dim MyChar() As Char = MyString.ToCharArray
   Array.Reverse(MyChar)
   MyString = New String(MyChar)
 End If
 Dim BufferSize As Size = e.Graphics.MeasureString(MyString, Font).ToSize
 Dim Buffer As New Bitmap(BufferSize.Width, BufferSize.Height)
 Dim g As Graphics = Graphics.FromImage(Buffer)
 g.Clear(BackColor)
 g.DrawString(MyString, Font, Brushes.Black, 0, 0)
 Buffer.RotateFlip(RotateFlipType.Rotate270FlipNone)
 e.Graphics.DrawImage(Buffer, 0, 0)
 g.Dispose()
 Buffer.Dispose()
End Sub

Private Sub CheckBox1_CheckedChanged(ByVal sender As System.Object, _
       ByVal e As System.EventArgs) Handles CheckBox1.CheckedChanged
 Invalidate()
End Sub
///

p.s. You can rotate the graphics object instead of drawing to a bitmap
first, but I found that can cause odd behaviour on transparent child
controls of a transparent parent, so I now always draw to a bitmap and
rotate that.