Microsoft's new consumer operating system was the top-selling software package last month, while "The Sims" continued to rule the computer game market, according to PC Data. The "step-up" version of Windows Me was No. 1 in the research firm's software sales rankings for September, while the expansion pack for "The Sims" and the full version of the simulation game were No. 2 and 4, respectively. The "Conquerors" expansion for Microsoft's "Age of Empires" strategy game was No. 3.