THE NASDAQ COMPOSITE INDEX fell 112.88, or 2.8%, to close at 3981.57, after dropping 90 points Friday. The Dow Jones Industrial Average finished down 48.44 points, or 0.5%, to 10685.12 after falling 110 points on Friday. Other major indexes fell. The Standard & Poor’s 500-stock index dropped 15.90 to 1464.29 and the New York Stock Exchange Composite Index sank 4.38 to 651. Joseph DeMarco, a managing director at HSBC Asset Management Americas, said the market was pressured by concerns about the outlook for corporate earnings, caution ahead of Mr. Greenspan’s address on the state of the economy and data that could provide a clearer indication of the interest-rate picture.