You can't just walk into Compunet in South Central, you have to ring the bell. Behind a barred security door typical of the homes and small businesses in the area, and equipped with a warning system that lets employees know if the door's ajar, this Compunet franchise store — a small, helpful, competent sales-and-repair business — is thriving despite such security measures. Forty years ago, this stretch of Vermont Avenue was a thriving business thoroughfare, but many things happened both economically and socially over the decades to depress the street. As a result, south of USC, Vermont Avenue is almost a wasteland. Yet the surrounding neighborhoods are jammed with people, including many who work at home, many who have teenagers, and many who need computer hardware and software help, upgrades and equipment. The large chains make only spotty appearances in the Vermont Corridor, so when Compunet opened a franchise here five years ago, it was an indicator of all the personal-computer activity alive and well in South Central. When we asked Compunet's local owner, Giovanni, why he would open a computer store in such a challenging location, he explained plainly that locals had asked him for it. Good service, fair prices, good guy. 8712 S. Vermont Ave., L.A. (323) 750-8881 or (800) 580-8787.