This document contains guidance for managing the threats of computer viruses, Trojan horses, network worms, etc. and related software along with unauthorized use. It is geared towards managers of end-user groups, managers dealing with multi-user systems, personal computers, and networks. The guidance is general and addresses the vulnerabilities that are most likely to be exploited. This document emphasizes that organizations cannot effectively reduce their vulnerabilities to viruses and related threats unless the organization commits to a virus prevention program, involving the mutual cooperation of all computer managers and users. The guidance is aimed at helping managers prevent and deter virus attacks, detect when they occur or are likely to occur, and then to contain and recover from any damage caused by the attack. The virus prevention program centers on strong user education, software management, the effective use of system controls, monitoring of user and system activity to detect abnormalities, and contingency procedures for containing and recovering. Nine references and 18 suggested readings are provided. (Author/DB)