Investors drove the stock market lower for a second straight day Friday as they grew anxious that earnings growth was faltering. Weaker earnings at JPMorgan Chase dragged bank stocks lower. And big drops in once-soaring tech stocks pushed the Nasdaq composite down for a third week. "The market has been trying to come back, but each time the selling just picks up," said Quincy Krosby, a market strategist at Prudential. "The buyers are just not stepping in." So much for buying the dip.