Installing an anti-virus or a security software, after installing Windows is a must. This helps protect our Windows computer from viruses and other security threats. It is also important to keep your security software up to date at all times! While the built-in Windows Defender in Windows 8 does a great job, some of you may want to opt for a third-party free antivirus software instead. Here are some very nice free antivirus software available for Windows 8, Windows 7 & Vista you might want to check out.
Free AntiVirus software for Windows

I have included only those antivirus programs which offer full real-time protection, and are not just stand-alone scanners!
1. Microsoft Security Essentials
Microsoft Security Essentials is Microsoft’s free antivirus offering to users of genuine Windows 7, Vista & XP users. (Windows 8 includes Windows Defender). It is specifically designed for individual consumer PC use using the smallest resource footprint possible to provide complete anti-malware protection and will include a new protection technology, as part of the Microsoft anti-malware engine, called Dynamic Signature Service (DSS).
Avira AntiVir offers you basic protection & protects your computer against dangerous viruses, worms, Trojans and costly dialers.
avast! Free Antivirus is perfect for people who send e-mails and surf popular websites. Its Anti virus and anti-spyware engine provides reliable protection against viruses, spyware, rootkits, trojans and other forms of malicious software.
4. Bitdefender Free Antivirus Edition
The free edition of its antivirus tool uses one of the world’s most effective antivirus engines, ICSA Labs certified scanning engines found in other BitDefender products for free. Thereby allowing you to enjoy basic virus protection for no cost at all. It includes a Real-time Shield.
AVG Anti-Virus Free lets you Surf & search with confidence, while LinkScanner, keeps you safe from select sites. AVG gives you online and offline protection from viruses, spyware, and other malware. Incidentally LinkScanner for some reasons is known to block several legit websites and security help forums, for some reasons, best known to them. Our TWC Security Forum is also blocked by them. More on this here.
Apart from these freeware if you’d like to suggest any more freeware antivirus software, do share below.
Go here if you are looking for free Internet Security Suites or free firewall software for your Windows computer.
ZoneAlarm Free Antivirus + Firewall, Kingsoft Antivirus, PC Tools Free Antivirus, Baidu AntiVirus may also interest you.
