According to the Small Business Administration, about 34% of business with fewer than 500 employees close within two years of opening, and 50% fold after four years. Here, New York Times writer Laura Randall tells the stories of some small-business owners who have become part of those statistics in Lessons Learned the Hardest Way, by Going Belly-Up (registration required). Their stories provide lessons in business that could be valuable to any company's survival.