Faced with ubiquitous signs of global economic meltdown, investors sold stocks in force on Tuesday, dragging the broad market indexes down near the lows reached last November. The Standard & Poor’s 500 index, weighed down by financials, fell 4.56%, while the Dow Industrials sank 3.8%, falling to within a fraction of its November 2008 low. Among the hardest hit sectors were bank stocks, down 10%, oil service stocks, down 8.2%, and semiconductor stocks, which fell 6.7%