Malware is the term for malicious software that you unwittingly download on your computer when you click on links in emails from scammers or fall prey to phishing and download the program from a phony website to which you were lured in the belief that it was a legitimate website.
One of the most common and dangerous types of malware is the keystroke logging program which is often referred to as a Trojan horse. Once this malware is installed on your computer, the scammer is able to access all of the information on your computer and can provide the scammer with access to your bank accounts, credit cards, brokerage accounts or any other information that is contained on your computer.
Never click on links unless you are absolutely sure it is legitimate. Also make sure you have an operating firewall on your computer and your computer security software is up to date.