restricting date text box between certain dates

My userform uses a date picker, so all dates entered in the text box "txtsumfrom" will be in (USA) short date format. I had code to allow blanks, and to ensure the value was in date format (in case they wrote over the dater picker) - but I also want to add a rule that the entered date could not be before a certain date (in this case, 7/1/14) or a future date). So I added the code highlighted below. I don't get an error (yay me, I'm learning!), but it doesn't work either!

I also need to know what code to not allow the dates. As is, it just is suppose to give the message box, but will still allow the forbidden date value. Any help is greatly appreciated!

Private Sub txtsumfrom_Exit(ByVal Cancel As MSForms.ReturnBoolean)

  If txtsumfrom.Value = "" Then
    Exit Sub

  Else

    'check date format
    If Not IsDate(txtsumfrom) Then
      MsgBox "Plese enter a valid date."
      Cancel = True
    If txtsumfrom.Value < "7/1/2014" Then
        MsgBox "You cannot enter a date before July 1, 2014."
    If txtsumfrom.Value > Today Then
        MsgBox "You cannot enter a date in the future."
    End If
    Exit Sub
  End If

End Sub

-HeyInKy