Hackers and spammers may be using your computer right now. They invade secretly and hide software to get access to the information on your computer. They can spy on your Internet surfing, steal your personal information, and use your computer to send spam to other computers without your knowledge. Spammers may send you an email with attachments, links or images which, if you click on or open them, install hidden software. Sometimes just visiting a website or downloading files may cause a “drive-by download,” which installs malicious software that could turn your computer into a “bot””]
Source: https://www.cuinfosecurity.com/minimize-effects-malware-a-733