Less than three years ago, Richard Taylor sang the tenor lead opposite Beverly Sills in the New York City Opera production of Manon. Today he runs the first retail supermarket for computer software, Programs Unlimited, in Jericho, N.Y.

"It was a slow transition," the 34-year-old Taylor recalls. "Finally, I was more interested in programming and computers than in singing opera."

Located in a small shopping center, Programs Unlimited offers about 800 different programs, from a $10 word game to a $2,000 general accounting package that will sort accounts payable from accounts receivable. A key attraction of the store is that it offers the customer the opportunity to try the product out before he buys it. The store has eight demonstration computers and a computer-wise staff.

Despite the overhead costs of Programs Unlimited, Taylor claims his prices are competitive. He believes the supermarket concept will prove increasingly attractive to manufacturers, who are becoming more "retail sales conscious."

Programs Unlimited, which is owned by the Jericho-based franchising firm Cut & Curl, went public in September, just one year after Taylor opened shop.

As for his career switch, Taylor says that isn't as surprising as it seems. When he was a performing-arts major in college, a leading computer firm recruited programmers at the music school. The company's research department had discovered that musicians make excellent programmers, because they can deal with structure without losing their creativity. The music-computer connection "struck me as odd," he says, "until the last few years."