There are many antivirus programs out there. How can you tell what works, what doesn't and what's worth the price?
First, it is important to understand what a virus is so that you know what you are actually protecting your computer against.
A virus IS
A program or script that runs on your computer that either changes the way the computer behaves in an unwanted or malicious way or compromises/steals your data, privacy or identity. Typically viruses do not announce themselves and run silently to gather as much information as possible.
A virus is NOT
A webpage. This is a common misconception. If you've ever seen a message pop up such as "This computer has been infected by a virus... Call Microsoft at 1 (800) SCA - MYOU" you have found yourself on a webpage that is trying to trick you into thinking you have a virus. This is commonly referred to as "scareware" and can be easily removed by restarting your computer. The entire experience is built on a webpage that you somehow came across. Once the page is closed, the threat is gone. The scam? These types of websites aim to get you to call the support line, have one of their technicians remote into your computer, and "fix" the problem for a hefty fee. If you have experienced this, know that it is very rare they go after your personal information in these cases--they simply want the payout at the end of the service.
There are two basic kinds of Antivirus programs:
Blacklist antivirus programs operate with "virus definitions" or program files that tell the antivirus program exactly what to look for. Big companies such as Norton and McAfee are always looking for the latest threats and viruses to hit computers and once they learn of a new virus, they update the virus definitions to be on the lookout. This blacklist system works for most home users who do not have really sensitive data.
A whitelist antivirus system takes a more secure approach to computer protection. The program blocks absolutely all programs and scripts UNLESS they have been specifically marked as OK or are on the whitelist. While this method is more secure and has a much higher success rate of stopping viruses, it can become cumbersome when programs you intentionally download are blocked and you have to reconfigure the whitelist regularly.
What kind of Antivirus do you need?
I like to think that the answer to this question depends on how sensitive your data is. If you run a business off of your computer, I would absolutely recommend a strict antivirus program that operates using a whitelist system. While there are many systems out there that will accomplish this (most paid-for antivirus) we would, of course, recommend our monitoring and management service. We install PCMatic antivirus on our client's computers and we also manage your whitelist internally. Whenever you have a program that needs to run that is being blocked, we can take care of it without you having to dive into the settings and figuring out how to manage the whitelist yourself.
If you are a home user and your documents are not too sensitive, you have backups of files, and you pretty much just use your computer for pictures and Facebook, you really do not need a paid-for antivirus service and the built-in Windows Defender will be enough for you.