There are many ways that a PC operating system can go wrong. Knowing the symptoms and what they mean is key in being able to fix the many problems you may encounter. Operating system issues can be grouped into different categories based on what causes them, such as boot problems, missing files, configuration files, and so on. This course discusses some common symptoms of PC security issues, such as slow performance, security alerts, files disappearing, and renamed system files. This course also discusses the best practices to adopt for removing malware from your system and improving security.