conn.ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=e:\\;Extended Properties=dBASE IV;User ID=;Password=;";
                conn.Open();
                OleDbCommand comm = conn.CreateCommand();
              string ttime = "13/03/2014 00:00:00";
            comm.CommandText = @"SELECT  PRODUKT, NOMER, FEMGN, FEOBS, DATA, TIME FROM ANALIZ  WHERE [DATA] > #" +max + "# or ([DATA] = #" + max + "# and [TIME] > #" + maxtime + "#)";
                dt.Load(comm.ExecuteReader());
                label2.Text ="row: "+ dt.Rows.Count.ToString() + " column: " + dt.Columns.Count.ToString();
                dataGridView1.DataSource = dt;

    public void ConvertMe() {         
                for (int tt = 0; tt < this.dataGridView1.RowCount - 1; tt++)
                {
                    string o = dt.Rows[tt][1].ToString();
                    var fromEncodind = Encoding.GetEncoding(1252);//из какой кодировки
                    var bytes = fromEncodind.GetBytes(o);
                    var toEncoding = Encoding.GetEncoding(1251);//в какую кодировку
                    string nom = toEncoding.GetString(bytes);
                    dt.Rows[tt][1]= nom; 
                }