Randomize Picturebox VB.Net

How can I random my pipes like in flappy bird? These code I've used, but my problem is, the pipes are not random. Where P1 - Picturebox2 are pictureboxes for pipes. Pipe1 to Pipe5 are boolean these will check the pipes if it's inside the screen.

    Private Sub ObsM_Tick(sender As Object, e As EventArgs) Handles ObsM.Tick
    Dim rndom As Integer
    Randomize()
    rndom = CInt(5 * Rnd()) + 1

    P1.Left = P1.Left - pspeed
    P2.Left = P2.Left - pspeed
    S1.Left = S1.Left - pspeed

    If rndom = 1 Then
        If P1.Left < 0 And P2.Left < 0 Then
            If pipe1 = True Then
                P1.Left = P1.Left + lpipes
                P2.Left = P2.Left + lpipes
                S1.Left = S1.Left + lpipes
                b1 = True
                pipe1 = False
            End If
        End If
    End If

    P3.Left = P3.Left - pspeed
    P4.Left = P4.Left - pspeed
    S2.Left = S2.Left - pspeed

    If rndom = 2 Then
        If P3.Left < 0 And P4.Left < 0 Then
            If pipe2 = True Then
                P3.Left = P3.Left + lpipes
                P4.Left = P4.Left + lpipes
                S2.Left = S2.Left + lpipes
                b2 = True
                pipe2 = False
            End If
        End If
    End If

    P5.Left = P5.Left - pspeed
    P6.Left = P6.Left - pspeed
    S3.Left = S3.Left - pspeed

    If rndom = 3 Then
        If P5.Left < 0 And P6.Left < 0 Then
            If pipe3 = True Then
                P5.Left = P5.Left + lpipes
                P6.Left = P6.Left + lpipes
                S3.Left = S3.Left + lpipes
                b3 = True
                pipe3 = False
            End If
        End If
    End If

    P7.Left = P7.Left - pspeed
    P8.Left = P8.Left - pspeed
    S4.Left = S4.Left - pspeed
    If rndom = 4 Then
        If P7.Left < 0 And P8.Left < 0 Then
            If pipe4 = True Then
                P7.Left = P7.Left + lpipes
                P8.Left = P8.Left + lpipes
                S4.Left = S4.Left + lpipes
                b4 = True
                pipe4 = False
            End If
        End If
    End If

    P9.Left = P9.Left - pspeed
    PictureBox2.Left = PictureBox2.Left - pspeed

    If rndom = 5 Then
        If P9.Left < 0 And PictureBox2.Left < 0 Then
            If pipe5 = True Then
                P9.Left = P9.Left + lpipes
                PictureBox2.Left = PictureBox2.Left + lpipes
                pipe5 = False
            End If
        End If
    End If

    If Scorep.Text > 9 Then
        pspeed += 0.5
    ElseIf Scorep.Text > 29 Then
        pspeed += 0.6
    ElseIf Scorep.Text > 49 Then
        pspeed += 0.7
    End If

    'P9.Left = P9.Left - pspeed
    'PictureBox2.Left = PictureBox2.Left - pspeed
    'If P9.Left < 0 And P10.Left < 0 Then
    'P9.Left = P9.Left + 920
    'P10.Left = P10.Left + 920
    'End If
End Sub