Viruses are harmful computer programs that can be transmitted in a number of ways. Although they differ in many ways, all are designed to spread themselves from one computer to another through the Internet and cause havoc. Most commonly, they are designed to give the criminals who create them some sort of access to those infected computers.
Ransomware is a type of malware that accesses a victim's files, locks and encrypts them and then demands the victim to pay a ransom to get them back. Cybercriminals use these attacks to try to get users to click on attachments or links that appear legitimate but actually contain malicious code. Ransomware is like the "digital kidnapping" of valuable data – from personal photos and memories to client information, financial records and intellectual property. Any individual or organization could be a potential ransomware target.
The terms "spyware" and "adware" apply to several different technologies. The two important things to know about them is that:
They can download themselves onto your computer without your permission (typically when you visit an unsafe website or via an attachment)
They can make your computer do things you don't want it to do. That might be as simple as opening an advertisement you didn't want to see. In the worst cases, spyware can track your online movements, steal your passwords and compromise your accounts.