Every computer must run some core software known as an Operating System, or OS for short. The three most common OS’s are Windows (of multiple versions), Mac, and Linux. 

Malicious software, or malware for short, is broken up into several categories. These are virus, Trojan, and worm for example, and they can serve many purposes. Each malware is classified by the method it uses to infect and spread. A virus is actually quite rare anymore, and infects by attaching itself to an otherwise harmless file, and then spreading to other files as they’re opened. A worm actively seeks to exploit open vulnerabilities to spread itself to other computers, but doesn’t infect files themselves. And a Trojan generally infects by pretending to be something harmless. For the most part, Trojans are the most frequently encountered form of malware on the internet, and for a good reason. They prey on most people’s inability to distinguish fake malicious programs from legitimate ones.

The first method of infection is by website scripts that pop up fake, but very realistic-looking windows warning you of problems with your computer. These are generally designed to look nearly identical to popular antivirus warning windows. Usually they are written in such a way that clicking anywhere in the window at all, even in some cases clicking the X to close the window, instead gives the software permission to download and install itself. The best way to avoid this sort of attack is to kill the window entirely without clicking in it. You can do this either by going to task manager (pressing ctrl-alt-esc, all at the same time), finding your browser, and choosing End Task, or by possibly just closing the window by pressing Alt-F4 or Ctrl-W (these combinations work in most browsers and all versions of Windows). If you do end task on your internet browser and the threatening window is still there, either it’s still running as a separate browser (look for more copies of Internet Explorer, Firefox, or Chrome), or it’s not running in the browser anymore. In these cases, either it’s legitimate (your antivirus really is stopping it), or it’s already managed to get a foothold on your computer and the start of an infection. In these cases, it’s generally best to let a professional take over. If it goes away, you’re likely ok. However, if you start getting strange windows and programs later, its best to get it looked at and cleaned by professionals.

The other method for infections to occur is by pretending to be something that would entice users to download it, such as a free game, or a free utility that claims to be able to make your computer run better or faster somehow. Any of these types of utilities that you run will claim to find numerous problems with your computer, but also claim to be unable to fix them without “upgrading” to a paid version of the software. For the most part, these programs tend to be either truly malicious in some cases, or simply ineffective in the case where they are not malicious. There are a few exceptions, however, but that’s, again, outside the scope of this article.

Generally, your safest bet is to install a legitimate and well-known antivirus software program (after checking reviews and feedback to ensure that it’s effective), that helps flag known malicious websites. Most antivirus packages do this in some way when you are searching online via Google or Yahoo or any of the major search websites. Avoid clicking on suspicious links, avoid downloading software that sounds too good to be true, and above all, make sure your security software is updated on a daily basis.

This brings up the final point. NO antivirus program is going to be 100% effective. Every antivirus works from a database of known malware, and small variations can mean that something goes undetected. New variations are released every single day in order to try to get around an antivirus’s shields. If you find yourself infected despite up-to-date protections, it isn’t necessarily the fault of the antivirus. Sometimes it just doesn’t have that infection in its database yet.   A great preventative measure is to install a pop up blocker to your browser.  Adblock Plus (ABP) is an open-source content-filtering and ad blocking extension for Mozilla Firefox, Google Chrome, Internet Explorer, Opera, Safari, and Yandex Browser web browsers.