A limited-use browser and related security system control access to content stored on a server computer linked to a network. The security system secures the content on the server and only permits it to be downloaded to a client computer running the limited-user browser or a general purpose browser executing an add-in security module providing the same functions as the limited-user browser. The limited-use browser or module secures the downloaded content on the client computer and displays it in a "view-only" mode. While the secured content is being displayed, menu selections, key combination, or pointing device commands initiated on the client computer that would modify the content or create a copy on another medium are either disabled as a default or monitored to determine if the action is permitted.