Having anti-virus software on your computer is important if you accidentally download a malicious piece of software that was created to steal your personal information, account information, images or various other information that could be used for criminal activity.
Many people might think that you are most likely to get a virus from surfing dodgy porn sites, although this might be true for a small percentage of sites out there, most of the time the real threat comes from unscrupulous download sites like CNET, Brothersoft, Softsonic and others.
These sites distribute software applications with very low standards and will approve pretty much any piece of software that might be tainted with malicious programs that will hurt your computer or steal your information.
An anti-virus software is a piece of software that runs in the background
on your computer and scans your email, files, downloads and network activity
for malicious software or files that could harm your computer or privacy
Most anti-virus software nowadays comes with a firewall, real-time file scanner and email scanner.
Virus creators make viruses because they benefit from it financially, or to show off their skills to the "blackhat hacker community", If you've seen the movie "Hackers", you might have seen how everyone knew the main characters "screen name" due to a worm he had programmed that infected a lot of computers.
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