Public Class Form1

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

        If TextBox1.Text.Contains("Virus") Then
            MsgBox(Vius Detected, MsgBoxStyle.Critical)
        Else
            MsgBox("No Virus Detected")
        End If
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Dim alltext As String = "", lineoftext As String = ""
        OpenFileDialog1.Filter = "All Files | *.*"
        OpenFileDialog1.ShowDialog()
        If OpenFileDialog1.FileName <> "" Then

        End If
        Try
            FileOpen(1, OpenFileDialog1.FileName, OpenMode.Input)

            Do Until EOF(1)
                lineoftext = LineInput(1)
                alltext = alltext & lineoftext & vbCrLf
            Loop
            TextBox1.Text = alltext
        Catch
        Finally
            FileClose()
        End Try
    End Sub