NEW YORK (Reuters) - Stocks fell at the open on Friday after retail sales unexpectedly dropped last month and as results from major banks failed to impress investors. The Dow Jones industrial average fell 45.85 points or 0.31 percent, to 14,819.29, the S&P 500 lost 5.89 points or 0.37 percent, to 1,587.48 and the Nasdaq Composite dropped 10.05 points or 0.3 percent, to 3,290.11. Despite the drop, the S&P was on track to post its best week since the first one of the year. (Reporting by Rodrigo Campos; Editing by Bernadette Baum)