Microsoft released an security update designed to limit the AutoPlay/AutoRun functionality in Windows 7’s precursors. Essentially, following the implementation of the refresh, the AutoPlay/AutoRun will no longer display the “Install or run program” option for USB drives. “In Windows XP, Windows Vista, Windows Server 2003, and Windows Serer 2008, AutoRun entries were populated for all devices that had mass storage and had a validly formatted AutoRun.inf file in the root directory. This included CDs, DVDs, USB thumb drives, external hard disks, and any volume that exposed itself as mass storage. This update disables AutoRun entries in AutoPlay, and displays only entries that are populated from CD and DVD drives. Effectively, this prevents AutoPlay from working with USB media,” explained Microsoft in KB971029 article.