Computer Virus – a computer program that can copy itself and infect a computer without permission or knowledge of the user. Computer viruses can cause erratic behaviour and can result in system crashes and the loss of user data.

Spyware – Spyware is computer software that is installed without the user’s knowledge. Its aim is to intercept or take partial control over the user’s interaction with the computer. Spyware can secretly monitor user behaviour, such as websites visited, it can collect various types of personal information, and change your computer settings.

Malware – Short for malicious software, Malware is any software used to disrupt computer operation, gather sensitive information, or gain access to private computer systems. Malware is sometimes found embedded in programs supplied officially by companies, e.g., downloadable from websites, that appear useful or attractive, but may have, for example, additional hidden tracking functionality that gathers marketing statistics.