A weakening U.S. dollar and encouraging news on U.S. housing sales and Europe's economy drove stocks higher Monday but failed to persuade big investors to join in. The Nasdaq, the S&P 500 and the NYSE composite each finished 1.4% higher. The Dow added 1.3% as it reached a new closing high for the year. The IBD 100 gained 1.7%, outperforming the major indexes. Volume was down on both major exchanges, continuing the recent pattern of lackluster