Random Number Gen with no duplicates - vb.net

Hi Experts,

I'm trying to build a simple number generator (winform) app VB-Express 2010.

***********************************************
** Label1  Label2  Label3  Label4  Label5  Label6  **
**                                                                                        **
**                            BUTTON1                                        **
******************************************

Click Button 1, all labels will generate numbers between 1, 6
 - thias works great.

But, I want to prevent duplicate PLEASE!

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    End Sub

    Dim objRandom As New System.Random( _
  CType(System.DateTime.Now.Ticks Mod System.Int32.MaxValue, Integer))

    Public Function GetRandomNumber( _
      Optional ByVal Low As Integer = 1, _
      Optional ByVal High As Integer = 100) As Integer
        ' Returns a random number,
        ' between the optional Low and High parameters
        Return objRandom.Next(Low, High + 1)
    End Function

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim intDiceRoll1 As Integer
        Dim intDiceRoll2 As Integer
        Dim intDiceRoll3 As Integer
        Dim intDiceRoll4 As Integer
        Dim intDiceRoll5 As Integer
        Dim intDiceRoll6 As Integer

        intDiceRoll1 = GetRandomNumber(1, 6)
        intDiceRoll2 = GetRandomNumber(1, 6)
        intDiceRoll3 = GetRandomNumber(1, 6)
        intDiceRoll4 = GetRandomNumber(1, 6)
        intDiceRoll5 = GetRandomNumber(1, 6)
        intDiceRoll6 = GetRandomNumber(1, 6)

        Label1.Text = (intDiceRoll1.ToString)
        Label2.Text = (intDiceRoll2.ToString)
        Label3.Text = (intDiceRoll3.ToString)
        Label4.Text = (intDiceRoll4.ToString)
        Label5.Text = (intDiceRoll5.ToString)
        Label6.Text = (intDiceRoll6.ToString)
    End Sub

Select allOpen in new window

Thanks,
Roberto (novice)