Imports Bytescout.Spreadsheet
Imports System.Diagnostics
Imports System.IO

Module Module1

    Sub Main()
        ' Open existing XLS file
        Dim spreadsheet As New Spreadsheet()
        spreadsheet.LoadFromFile("Input.xls")

        ' delete output file if exists already
        if File.Exists("Output.xlsx") Then
            File.Delete("Output.xlsx")
        End If

        ' Save it as XLSX
        spreadsheet.SaveAs("Output.xlsx")

        ' open output document in default viewer
        Process.Start("Output.xlsx")

    End Sub

End Module