Volatility be damned—a '90s icon makes a risky comeback.

Rockwell, an inventor and entrepreneur who founded and later sold an Internet service provider called Softaware in 2000, says he always regretted cashing out of the stock market after the 1987 crash.

At the time, he was studying business administration at the University of California at Berkeley and he put everything he had in cash for several years. "Someone told me I would have doubled my money if I'd invested after that happened," he recalled. "I vowed that the next time someone says, ‘This is the worst market in 100 years,' I'm not going to miss my opportunity."

He believed that opportunity had arrived in October after the Dow fell below 10,000 from a high of 14,164. "I decided to follow Warren Buffett's advice to ‘be fearful when others are greedy and be greedy when others are fearful,' " he says.

Rockwell signed up for StreetSmartPro, software designed for active investors that is available to Charles Schwab customers, and he proceeded to buy shares in established names like General Electric, Intel, and Apple. They all tanked. "It's been a real education for me to understand that what makes a strong stock is sometimes completely different from what makes a great company," he says.

So far, he is down 20 percent since he began day trading a month and a half ago. "It's been hard. It's been brutal, actually," he says. "Every day is like a complete surprise." But he vows to continue, believing that over time he will turn a profit.

Cathy Stockstill, a day trader who began playing the market during the first dot-com boom and, unlike many of her fellow investors, stayed with it, says the seesawing stock market has been "excellent for me."