Stocks held on to their gains early Tuesday afternoon, as all three major indexes moved to new high ground. The Nasdaq climbed 1.3%. The S&P 500 and the Dow Jones industrial average each rose 1%. Volume remained solidly higher on both the NYSE and the Nasdaq compared with the same time Monday. In the stock market today, the Dow rose above its 2007 high. The S&P 500 hung just below its high from that same year, and the Nasdaq staked out a fresh