Viruses, malware, and ransomware are all bad, but there are subtle differences between each. Malware covers any software meant to cause harm to a computer. It can be innocuous but irritating like a pop-up ad or it can be as severe as hacking your webcam. Viruses are like malware in terms of reach but they self-replicate causing an 'infection' to your computer, hence its name. Viruses can be caught via email attachments, dangerous links, or even disguised pop-ups.  Ransomware is designed to block access to your system until a 'ransom' is paid. They're more likely to affect larger institutions but sometimes the average user can be caught out by such a problem. A good paid antivirus software tool can fight all three of these.