If you have a computer you need to have an anti-virus.  That's the very basic.  Anti-virus is not an accessory to the computer but an essential program to shield it from destructive programs that may jeopardize your system.

The top rated anti-viruses are listed here to help the computer users compare the best anti-virus at present time.  They were reviewed by the well known review organizations TopTenREVIEWS and PC Anti Virus Reviews.

Ranked #1 of 25 in Anti-virus Software by TopTenREVIEWS
Ranked #2 of 8 in Anti-virus Software by PC Anti Virus Reviews
BitDefender Antivirus Pro 2011 Provides 3 PCs with one year of Protection against viruses, spyware, and identity theft without slowing you down. Features include: IM Encryption, to keep your private chats private; Search Advisor, for advance warnings about risky websites—displayed right in your search results; Video Tutorials, which guide you through the most frequently encountered security challenges; a customizable dashboard, which allows you to view how much or how little you want to; Gamer Mode, for secure gaming at top speed; Laptop Mode, for Prolonged battery life; automatic hourly updates; Home Network Management; free 24/7 technical support; and more!

Product Features
  • Download, share and open files from friends, family, co-workers?or even total strangers. Protect against viruses and other malware, Scan all Web, e-mail and instant messaging traffic in real-time
  • Protect your identity by blocking websites that attempt to steal your credit card data, Prevent personal information from leaking via e-mail, Web or Instant Messaging
  • QuickScan utilizes in-the-cloud technology to uncover viruses in 60 seconds, with minimal strain on system resources and Laptop Mode prolongs battery life, while on the go
  • Choose your view by matching the dashboard to your level of PC knowledge by selecting between Basic, Intermediate, or Expert settings. Quickly and easily create shortcuts to your most frequently used features and controls
  • Free technical assistance, 24/7! Video Tutorials help you navigate through common security challenges, Built-in Help Desk finds solutions to the most FAQs, Online Knowledge Base contains a library of articles and puts you in contact with phone support

Ranked #2 of 25 in Anti-virus Software by TopTenREVIEWS
Ranked #3 of 8 in Anti-virus Software by PC Anti Virus Reviews
Kaspersky Anti-Virus 2011 defends against both known and emerging viruses, spyware and malware with streamlined technologies that won't slow you down. Kaspersky Anti-Virus keeps your digital identity and passwords safe and secure when you're shopping, banking, or social networking.

Product Features
  • Kaspersky Anti-Virus 2011 provides real-time protection from viruses, spyware, trojans, rootkits, bots and more, with technologies to keep your identity safe and secure
  • Hourly signature updates, best-in-class unknown threat protection, and application vulnerability alerts give you complete confidence
  • Small footprint, tiny updates and intelligent variable scanning lets your machine performto the max
  • Your digital identity and passwords are kept secure when you're shopping, banking or networking online
  • New Desktop Security Gadget for easy drag-and-drop virus scanning and instant access to all your security settings

Ranked #6 of 25 in AntiVirus Software by TopTenREVIEWS
Ranked #4 of 8 in AntiVirus Software by PC Anti Virus Reviews
AVG Anti-Virus 2011 offers real-time protection against today's most sophisticated threats. You will be able to chat, download and exchange files with confidence. Play games and watch videos without worry or interruption.

AVG Anti-Virus 2011 provides exceptional protection that won't get in your way
  • Safely download, share files and send messages using chat with AVG Online Shield
  • Stay safe on social networks with AVG Social Networking Protection - NEW!
  • Surf and search with confidence with AVG LinkScanner's real-time protection

Ranked #4 of 25 in Anti-virus Software by TopTenREVIEWS
Ranked #6 of 8 in Anti-virus Software by PC Anti Virus Reviews
Stay a step ahead of threats to your PC with fast, powerful protection. Norton AntiVirus 2011 detects and eliminates viruses, spyware, and other threats lying in wait to infect your PC, so you can chat, email, and share files safely. It provides rock-solid protection against hidden threats lurking in downloads, emails, and instant messages without slowing down your PC's performance. The result? You'll spend less time waiting for slow scans that bog down your computer and have more time to chat, download your favorite tunes and videos, and hang out at social networking sites.

Product Features
  • Norton AntiVirus 2011 offers fast, powerful protection that safeguards against viruses and spyware
  • Stop viruses and other threats before they can do damage
  • Stay safe with up-to-minute protection that won?t slow down your PC
  • Detect and eliminate spyware cybercriminals can use to steal your personal information
  • Know when applications are slowing down your PC, so you can make changes to improve performance

Ranked #5 of 25 in Anti-virus Software by TopTenREVIEWS
Ranked #8 of 8 in Anti-virus Software by PC Anti Virus Reviews
Antivirus protection is spelled "NOD32." Built on the award-winning ThreatSense engine, ESET NOD32 Antivirus software proactively detects and eliminates more viruses, trojans, worms, adware, spyware, phishing, rootkits and other Internet threats than any program available. No matter what your system, there is no better antivirus protection. ESET NOD32 Antivirus was awarded the "BEST Antivirus Solution" in 2007 and 2008 by AV-Comparatives.

Product Features
  • ThreatSense technology uses multiple layers of threat detection to deliver the most effective protection possible against new attacks
  • Typically when a new copy of ESET NOD32 replaces another antivirus product on a home computer the average user finds viruses or malware resident on the machine that were undetected by their previous antivirus product
  • ESET NOD32 Antivirus is lightning fast, so fast you won't even notice it's there
  • ESET NOD32 Antivirus is lean and mean, typically using just 44 MB of memory
  • You will receive the best possible proactive detection against malware, without enduring excessive system slowdowns and alerts, reboots or annoying false alarms