AVG Antivirus : AVG Anti-Virus Free Edition may only be used on one computer for personal use.

   AVAST : Free antivirus for ordinary internet use.

PCTools : With PC Tools AntiVirus Free, you are protected against basic cyber threats attempting to gain access to your PC.

   Comodo : This proactive system automatically isolates threats from untrusted files so they can't cause harm. Free version got lots of features that make comodo one of the best free antivirus around.

 Hijack This : Trend Micro HijackThis is a free utility that generates an in depth report of registry and file settings from your computer. HijackThis makes no separation between safe and unsafe settings in its scan results giving you the ability to selectively remove items from your machine.

  McAfee : McAfee makes commercial antivirus products, but it also offers some free tools for removing viruses. Specifically, it offers tools for removing Lovsan / Balster, Klez, Zafi, Mydoom, Bugbear, Sasser, Bagle

 Ad-Aware : Giving you the power to use the Internet when, where and how you want.Real-time protection against virus, spyware, trojans, rootkits, hijackers, keyloggers, and more! This all features for free.

 Windows Defender : Microsoft’s Windows Defender is a free anti-spyware utility for Windows. It’s not comprehensive, but it does a surprisingly good job of protecting Windows as long as you install it before an infection occurs.