Visual Basic 2010 Express help needed

Public Class Form1
    Dim port_name As String()
    Dim i As Integer
    Dim j As Integer

    Dim send_data As String
    Dim input As Integer = 0
    Dim receive_data As String
    Dim Ctr As Control
    Dim BRx(256) As Byte

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'Set up serialport 1

        SerialPort1.DataBits = 8
        SerialPort1.StopBits = IO.Ports.StopBits.One
        SerialPort1.Parity = IO.Ports.Parity.None

        'Set up Combobox comport 1
        cbb_comport.DropDownStyle = ComboBoxStyle.DropDownList
        cbb_baudrate.DropDownStyle = ComboBoxStyle.DropDownList
        cbb_stopbit.DropDownStyle = ComboBoxStyle.DropDownList
        cbb_parity.DropDownStyle = ComboBoxStyle.DropDownList
        cbb_databit.DropDownStyle = ComboBoxStyle.DropDownList
        cbb_flow.DropDownStyle = ComboBoxStyle.DropDownList

        cbb_comport.Sorted = True
        port_name = IO.Ports.SerialPort.GetPortNames()
        For Each comp1 In port_name
            cbb_comport.Items.Add(comp1)
        Next
        cbb_comport.SelectedIndex = 0
        'Set up combobox baudrate 1
        cbb_baudrate.Items.Add(2400)
        cbb_baudrate.Items.Add(4800)
        cbb_baudrate.Items.Add(9600)
        cbb_baudrate.Items.Add(14400)
        cbb_baudrate.Items.Add(19200)
        cbb_baudrate.Items.Add(38400)
        cbb_baudrate.Items.Add(56000)
        cbb_baudrate.Items.Add(57600)
        cbb_baudrate.Items.Add(115200)
        cbb_baudrate.Items.Add(128000)
        cbb_baudrate.Items.Add(256000)

        cbb_baudrate.SelectedIndex = 2
        'Set up combobox databit 1

        cbb_databit.SelectedIndex = 1




        btn_DisConnect.Enabled = False

    End Sub

    Private Sub btn_Connect_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_Connect.Click
        Timer1.Enabled = True
        Timer1.Interval = 500
        SerialPort1.PortName = cbb_comport.SelectedItem
        SerialPort1.BaudRate = cbb_baudrate.SelectedItem
        SerialPort1.DataBits = cbb_databit.SelectedItem


        SerialPort1.Open()
        Me.SerialPort1.DiscardOutBuffer()           'clear output buffer
        Me.SerialPort1.DiscardInBuffer()            'clear input buffer
        Me.SerialPort1.RtsEnable = False
        Me.SerialPort1.DtrEnable = False

        btn_DisConnect.Enabled = True
        btn_Connect.Enabled = False

        '----------------------------------------

        Me.Text = "Serial Communication" & "    " & "(Connected)"
        Panel1.BackColor = Color.Lime


        cbb_comport.Cursor = Cursors.No

    End Sub

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        For Me.i = 0 To 255
            BRx(i) = 0
        Next
        receive_data = SerialPort1.BytesToRead
        If receive_data = 0 Then Exit Sub
        If receive_data > 256 Then
            receive_data = 256
        End If
        For Me.j = 1 To receive_data
            BRx(input) = SerialPort1.ReadByte
            txt_receive.Text = txt_receive.Text & Chr(BRx(input))
            input = input + 1
        Next
        input = 0
        Timer1.Enabled = False


        For Me.i = 0 To 255
            BRx(i) = 0
        Next
        Timer1.Interval = 500
        Timer1.Enabled = True

    End Sub

    Public Sub delay(ByVal wait As Long)
        Dim i As Long
        For i = 0 To wait
        Next i
    End Sub

    Private Sub btn_DisConnect_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_DisConnect.Click
        SerialPort1.Close()
        Timer1.Stop()
        btn_DisConnect.Enabled = False
        btn_Connect.Enabled = True

        Panel1.BackColor = Color.Transparent

        btn_Connect.Enabled = True
        btn_DisConnect.Enabled = False
        cbb_comport.Enabled = True
        cbb_baudrate.Enabled = True
        cbb_databit.Enabled = True
        Me.Text = "MCU Firmware CheckSum" & "    " & "(Disconnected)"
    End Sub

    Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click
        txt_receive.Clear()
    End Sub

    Private Sub btnSend_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSend.Click

        send_data = 0
        For Me.i = 0 To Len(txtSend.Text) - 1
            send_data = Mid(txtSend.Text, 1 + i, 1)
            Me.SerialPort1.Write(send_data)
            Call delay(90000)
        Next i
    End Sub
End Class