Visual Basic

Public Class Form1
    Dim FILE_NAME As String = ("serial.txt")

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

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

        Do Until objReader.EndOfStream
            If txtserial.Text = objReader.ReadLine Then
                Startnot.Checked = False

                Form2.Show()
                Me.Hide()
            Else
                Try
                    If txtserial.Text = objReader.ReadLine.Trim Then

                    End If

                Catch Ex As Exception


                End Try
                Label1.Text = "Invalid CDKey"
            End If

        Loop
        objReader.Close()


    End Sub

    Private Sub Form1_Leave(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Leave
        If Me.Visible = False Then
            Form2.Show()
        End If
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        SetAttr(FILE_NAME, FileAttribute.Normal)
        Dim Dontshow As Boolean

        Dontshow = GetSetting(My.Application.Info.ProductName, "Options", "Dont Show Me", 1)

        If Dontshow = 0 Then
            Form2.Show()
            Call cookies()
            Exit Sub
        End If

        Startnot.Checked = True
    End Sub

    Private Sub Startnot_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Startnot.CheckedChanged
        SaveSetting(My.Application.Info.ProductName, "Options", "Dont Show Me", Startnot.CheckState)
    End Sub

    Private Sub cookies()

        Me.Close()
        My.Forms.Form2.Show()
    End Sub

End Class