At Gateway Inc. in the 1990s, Rob Cheng, senior vice president of worldwide sales, marketing and support, could see the problems lining up from his desk on the Iowa-South Dakota border. Customers were calling customer support lines complaining of slow machines, and there was no clear diagnostic system to efficiently address the customers.  In 1999 Cheng left Gateway to found PC Pit Stop, offering custom computer diagnostics and troubleshooting. Soon,