More computer viruses and more kinds of ways they infect your computer. If you do not use an antivirus software, see 5 pretty popular software used to protect your computer.
Avast! (Windows / Linux, Basic: Free, Premium $ 39.95 per year)

It was created 21 years old, Avast! is a long player in the market for antivirus software. Avast! has built a strong foundation of their philosophy by offering virus protection that is reliable and effective for free for home users. In addition, Avast! offers a variety of protection module which covers many aspects of your computer such as instant messaging, e-mail, P2P applications, and many more.
Microsoft Security Essentials (Windows, Free)

Microsoft Security Essentials is the newest addition to protect Microsoft-based computers. In place of the Windows Live OneCare and Windows Defender to offer more coverage than ever before. Software provided free for all users of Windows and various memberik protection threats such as viruses, malware, adware, and spyware
Avira (Windows, Basic: Free, Premium: $ 30 per year)

Avira is another antivirus application provided free of charge, although a free version of Avira does not offer much compared with other free offers. However, you still can rely on detecting viruses and malware protection, and rootkits. In addition, Avira also offers a Linux Live CD is filled with Avira recovery and system recovery applications are free options to help you to fight the virus.
ESET NOD32 Antivirus (Windows, $ 39.99 per year)

NOD32 has build a large user base over the years by having a small number of false threats and a high detection rate using ThreatSense system.
AVG (Windows, Basic: Free, Premium: $ 54.99 per year

Offer for free from AVG is the lightest, most easy, compared to the others. If you are looking for the most basic antivirus applications that detect spyware, and malware and viruses maintain the website in, AVG is one of the best.