Microsoft Corporation announced that John W. Thompson, chief executive officer of privately held Virtual Instruments and former chairman and CEO of Symantec Corp., was appointed to the company's board of directors, returning the board's size to 10 members. Thompson currently serves as CEO of Virtual Instruments, whose products are designed to ensure the performance and availability of applications deployed in virtualized and private cloud computing environments. Since 2009, Thompson has been an active investor in early-stage technology companies in Silicon Valley. Thompson currently serves on the board of United Parcel Service, and he has served on a number of government boards and commissions, including the Financial Crisis Inquiry Commission, the National Infrastructure Advisory Committee, and the Silicon Valley Blue Ribbon Task Force on Aviation Security and Technology.