Computer viruses contnue to pose a threat to the integrity and availability of computer systems.  This is especially true for users of personal computers.  A variety of anti-viruse tools are now available to help manage this threat.  These tools use a wide range of techniques to detect, identify, and remove viruses. This guide proivides criteria for judging the functionality, practicality, and convience of anti-virus tools.  It does not weigh the merits of specific tools, however it forms a basis with which readers can then evaluate which tools are best suited for target environments.