Dim strFileName As String
        fd.Title = "Open file dialog"
        fd.InitialDirectory = "D:\Folder"
        fd.Filter = "PDF files (*.pdf)|*.pdf|PDF files (*.pdf)|*.pdf"
        fd.FilterIndex = 2
        fd.RestoreDirectory = True
        If fd.ShowDialog() = DialogResult.OK Then
            strFileName = fd.FileName
            WebBrowser1.Navigate(strFileName)
        End If
    End Sub