.NET Make a MINECRAFT name checker!

Code
Public Class Form1



    Dim file As String

    Dim currentWorkerName As String

    Dim currentWorkerNameA As Boolean



    Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged

        TextBox1.ForeColor = Color.Black

    End Sub



    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

        If TextBox1.Text = "" Then

            MsgBox("Empty minecraft username!", MsgBoxStyle.Information, "@Available Notification")

            Return

        End If

        Dim wc As New Net.WebClient

        Dim res As String

        res = wc.DownloadString("https://minecraft.net/haspaid.jsp?user=" + TextBox1.Text)

        ListBox1.Items.Add(TextBox1.Text)

        If res.Contains("false") Then

            TextBox1.ForeColor = Color.LightGreen

            ListBox2.Items.Add(TextBox1.Text)

        Else

            TextBox1.ForeColor = Color.Red

        End If

    End Sub



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

        ofd.Filter = "Text Files (*.txt)|*.txt"

        ofd.ShowDialog()

        If Not ofd.FileName = "" Then

            file = ofd.FileName

            bgWorker.RunWorkerAsync()

        End If

    End Sub



    Private Sub bgWorker_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles bgWorker.DoWork

        If System.IO.File.Exists(file) = False Then

            Return

        End If

        Dim objReader As New System.IO.StreamReader(file)

        Dim count As Integer = 0

        Do While objReader.Peek() <> -1

            count += 1

            currentWorkerName = objReader.ReadLine()

            Dim wc As New Net.WebClient

            Dim res As String

            res = wc.DownloadString("https://minecraft.net/haspaid.jsp?user=" + currentWorkerName)

            If res.Contains("false") Then

                currentWorkerNameA = True

            Else

                currentWorkerNameA = False

            End If

            bgWorker.ReportProgress(count)

            System.Threading.Thread.Sleep(150)

        Loop

    End Sub



    Private Sub bgWorker_ProgressChanged(sender As Object, e As System.ComponentModel.ProgressChangedEventArgs) Handles bgWorker.ProgressChanged

        ListBox1.Items.Add(currentWorkerName)

        If currentWorkerNameA Then

            ListBox2.Items.Add(currentWorkerName)

        End If

    End Sub



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



    End Sub

End Class