System software and application software are two types of computer software. System software governs how a computer and its related devices operate, while application software is more specified toward user-oriented tasks, such as Web browsing and word processing.
Operating systems, device drivers and utility programs are included in system software, whereas the spans of application software is practically infinite.
Malicious software, or malware, is software designed to disrupt or compromise computers. Examples of malware include viruses, Trojan horses, rootkits and backdoors. Malware designed to gather information or spy on a user is often very difficult to detect. A significant amount of malware takes advantage of inherent weaknesses or oversights in other types of software.