Windows 7 Tip: 
ThreatFire features innovative real-time protection technology that provides powerful standalone protection or the perfect complement to traditional signature-based antivirus programs. ThreatFire’s patent-pending ActiveDefense technology offers protection against both known and unknown viruses, worms, trojans, rootkits, buffer overflows, spyware, adware and other malware. It uses behavioral analysis to hunt down and paralyze threats that are too new or too clever to be recognized by traditional “signature-based” antivirus software. Powerful protection against zero-day and emerging threats.
“ThreatFire 3’s ability to block installation of malware strictly by identifying bad behavior is phenomenal. It did a better (and faster) job than Norton AntiBot and even beat out Spy Sweeper, our current Editors’ Choice for signature-based anti-spyware. This free tool is an excellent addition to your security arsenal.”
Not bad… will surely give it a try.
Indeed threat file is a good AV. I had downloaded it already.