This document discusses 11 signs that a system has been hacked, including fake antivirus messages, unwanted browser toolbars, unexpected software installs, and unexpected data bundles. It recommends downloading a PDF from InfoWorld that provides tips and advice on identifying hacks and protecting yourself from their worst outcomes. The PDF is authored by Roger A. Grimes, a security expert with over 40 certifications who has been fighting malware and hackers since 1987.