Stocks opened on a strong footing Tuesday, starting higher in rising trade. The Nasdaq led with a 1% gain. The Dow Jones industrial average and S&P 500 each added 0.8% -- enough to lift the Dow into record territory above its October 2007 high. Volume was up 23% on the Nasdaq and 15% higher on the NYSE compared with the same time Monday. The stock market today opened to broad gains, with fewer than 1% of S&P 500 stocks posting losses in the early