I have been using Internet and Computers from 2000 and have experienced the efficiency of all the Anti-virus softwares like Mc Affee, Norton, Pc-illian, AVG etc but not even satisfied with any one of them because they occupy huge space and need more resources that an AV shouldn’t use. Another great dis-advantage is that they are not that effective, first they are corrupted by Virus and then they allow Virus to corrupt our system. funny huh .. After using AVAST Anti-virus for the past 3 years i have experienced not even a single problem becoz AVAST Anti-Virus uses very less resource and works effectively. But it was two days before my system totally got messed-up and i had no other way then to format my entire drive so i proceeded to do that so. After re-installing all the softwares i once again thought of installing the Avast AV but my friend Srinivasan recommended me to try Kaspersky Internet Security, so on taking his recommendation i installed the Kaspersky to my surprise i have never experienced such a good anti-virus software in my life. This AV is built with all the features a system requires and the main bit is that it uses very very less resource of ram. I recommend the following Anti-Virus for your OS. Only Anti-Virus: If you prefer to use only anti-virus software and already have another firewall installed for your internet security then download Kaspersky Internet Security and while installing select only the Anti-virus to install. Only Firewall: If you prefer to use only Firewall then download the Mcafee Desktop Firewall which doesn’t even needs a 10 mb of ram. It works like a gate system and has no extra features. Both Anti-Virus and Firewall: Well the ultimate answer from me is simply install the complete Kaspersky Internet Security.