Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
        Dim str As String = RichTextBox1.Text
        Dim nstr As String = str(0)
        For i As Integer = 1 To str.Length - 1
            If str(i) <> str(i - 1) Then
                nstr += str(i)
            End If
        Next
        RichTextBox1.Text = nstr
    End Sub

Those people who think they know everything are a great annoyance to those of us who do - Isaac Asimov