overwrite file question

Imports System.Threading
Imports System.IO.Ports
Imports System.ComponentModel
Public Class Form1

    Dim myPort As Array
    Delegate Sub SetTextCallback(ByVal [text] As String)
Dim file As System.IO.StreamWriter

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

        myPort = IO.Ports.SerialPort.GetPortNames()
        ComboBox1.Items.AddRange(myPort)

        Button2.Enabled = False

    End Sub

    Private Sub ComboBox1_Click(sender As System.Object, e As System.EventArgs) Handles ComboBox1.Click
    End Sub

    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        SerialPort1.PortName = ComboBox1.Text
        SerialPort1.BaudRate = ComboBox2.Text
        SerialPort1.Parity = Parity.None
        SerialPort1.DataBits = 8
        SerialPort1.StopBits = StopBits.One
        SerialPort1.Handshake = Handshake.None
        SerialPort1.Encoding = System.Text.Encoding.Default
        SerialPort1.Open()
        Button1.Enabled = False
        Button2.Enabled = True
        Button4.Enabled = True

    End Sub

    Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click

        SerialPort1.Write(RichTextBox1.Text & vbCr)
    End Sub

    Private Sub Button4_Click(sender As System.Object, e As System.EventArgs) Handles Button4.Click
        SerialPort1.Close()
        Button1.Enabled = True
        Button2.Enabled = False
        Button4.Enabled = False
    End Sub

    Private Sub SerialPort1_DataReceived(sender As System.Object, e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
        ReceivedText(SerialPort1.ReadExisting())


    End Sub

    Private Sub ReceivedText(ByVal [text] As String)
    file = My.Computer.FileSystem.OpenTextFileWriter("C:\Users\LENOVO\Desktop\SerialCom\textout.txt", False) 'Overwrite file
        file.Write(text)
        file.Close()
End Sub

End Class