How to convert .docx/.xslx file to .doc/.xls in asp.net 2.0

Question

Hi,

  how can i convert a .docx/.xlsx file to .doc/.xls file in asp.net 2.0 I tried with OpenXml but i think  the dll for that will be in .net  3.0 version. Please help. its urgent.

I tried with the following code, and while downloading unable to view the last inserted.

 protected void btnUpload_Click(object sender, EventArgs e)
    {
        // Read the file and convert it to Byte Array
        string filePath = FileUpload1.PostedFile.FileName;  
        string filename = Path.GetFileName(filePath);
        string ext = Path.GetExtension(filename);
        string contenttype = String.Empty;

        //Set the contenttype based on File Extension
        switch(ext)
        {
            case ".doc":
                contenttype = "application/vnd.ms-word";
                break;
            case ".docx":
                contenttype = "application/vnd.ms-word";
                break;
            case ".xls":
                contenttype = "application/vnd.ms-excel";
                break;
            case ".xlsx":
                contenttype = "application/vnd.ms-excel";
                break;
        }
        if (contenttype != String.Empty)
        {

            Stream fs = FileUpload1.PostedFile.InputStream;
            BinaryReader br = new BinaryReader(fs);
            Byte[] bytes = br.ReadBytes((Int32)fs.Length);

            //insert the file into database
            string strQuery = "insert into tbl_files(Name, ContentType, Data) values (@Name, @ContentType, @Data)";
            SqlCommand cmd = new SqlCommand(strQuery);
            cmd.Parameters.Add("@Name", SqlDbType.VarChar).Value = filename;
            cmd.Parameters.Add("@ContentType", SqlDbType.VarChar).Value = contenttype;
            cmd.Parameters.Add("@Data", SqlDbType.Binary).Value = bytes;
            InsertUpdateData(cmd);
            lblMessage.ForeColor = System.Drawing.Color.Green;  
            lblMessage.Text = "File Uploaded Successfully";
        }
        else
        {
            lblMessage.ForeColor = System.Drawing.Color.Red;   
            lblMessage.Text = "File format not recognised. Upload Word/Excel formats";
        }
    }



Thanks,