Because some of them suck.
Norton Antivirus software packages can be downloaded freely from the official Norton website. It should be noted that these are either 30 day trials or are basic packages and may not include certain protections.
Some free antivirus programs include: NOD32 and Kaspersky. The cheapest antivirus programs are the free ones but the protection may not be as great as the paid versions. Some free antivirus programs include: Avast Free, AVG Free, Avira, Bitdefender, Comodo, Immunet, Kingsoft, Microsoft Security Essentials and Panda Cloud Antivirus.
Simply download the installer for the antivirus, then run it. With some antivirus software you don't even need to install it!
AVG is a free antivirus program available on the internet. Other options for free antivirus software are Panda Security, Immunet, and, ZenOK. All are available for free via direct downloads from their respective websites.
The most cost effective antivirus would be one of the free ones. AVG Anti-Virus Free Avast! Free Antivirus Microsoft Security Essentials Comodo Antivirus Avira AntiVir Personal Panda Cloud Antivirus Immunet Protect FREE digital-defender Antivirus PC Tools AntiVirus Free
There are many competitors for the Norton Antivirus brand. Some of the more notable ones are McAfee, a pay antivirus program, and Avast, a free antivirus program available for download.
The companies that offer free antivirus software include Avast, AVG Anti-virus, Avira FREE antivirus, Bitdefender free edition, and Comodo Antivirus 6. Some others that may come in handy are Immunet and Kingsoft.
There are many sites where one can find the best free downloadable Antivirus Software. Some of them are Microsoft Security Essential, Avast Free Antivirus, AVG Anti-Virus Free and Avira Antivirus Free.
It's a good free antivirus.
Obviously not. Some antiviruses include it with it. Please note you might have to enable it. Also, some are free and some aren't. For example, I use Avast! for my antivirus, however, its VPN wasn't free.
BitDefender offers a free 30 day antivirus software that allows you try it before you buy it. You will have to supply some personal information before you can download it.
There are lots of places where someone can get free antivirus software trials. Some of these places are Mc Afee, Norton, Kaspersky, AVG and Zone Alarm.