Definition of Virus / Malware
A computer virus is a programme written to spread quickly and insidiously to other computers. It disrupts the operation of the infected computer to a greater or lesser degree. It can spread via any medium for exchanging digital data, such as the Internet, and particularly via e-mail messages or attachments.
What is the difference between a virus and malware?
The generic term for viruses is malware. The term virus is commonly misused to refer to all malware. There are different types of malware: viruses, worms, Trojan horses and logic bombs, some of which load into memory, others of which infect the hard disk directly. Viruses replicate and spread by inserting themselves into other software. Worms spread directly between computers, often via email, file sharing or the Internet. Trojan horses can be used to take control of an infected computer or to retrieve information from its victim.
A virus can either delete or corrupt data. There are also viruses known as ransomware, which encrypt all computer data and demand a ransom so that you can decrypt and recover your data.