Viruses are not the only thing that antivirus programs protect against. There are also worms, which attack your device and attempt to propagate across networks, and trojans that appear to be safe programs but are anything but — as they will lurk on your device and attempt to steal your account and financial information. 

You often find viruses, worms, and trojans hidden within seemingly legitimate software, or if you are downloading pirated content, you are also putting yourself at risk of accidentally executing malware on your machine.

Ransomware, too, is a serious threat to consumers and businesses today. Modern antivirus programs are often able to stop it in its tracks before it encrypts your machine and demands a ransom payment in return for a decryption key.

Spyware, coming in forms including software executables and mobile apps, can severely impact your privacy. Spyware will monitor your activities and collect your data, and in cases of stalkerware, may also log your phone calls, text messages, social media activity, and GPS location.

Antivirus apps and programs also protect against adware that can tap into your web history and flood you with pesky and potentially dangerous ads or notifications. Also known as nuisanceware, while not usually dangerous, nuisanceware can slow down your device, drain power, and make it close to impossible to browse the internet normally.

You should keep in mind that many variants of malware today are not limited to attacks against PCs — malicious software can also be found in seemingly benign mobile apps.