3. BITDEFENDER
Cheapest all-in-one available in market. Detects every new virus. The antivirus uses advanced technology algorithms and methods to identify security risks and blocks threats even before they try to harm your computer.
Pros: Flexible Tools, Easy Installation, Total Protection.
Cons: Heavy on Low Configured Machines.
2. AVAST
It is light on system & easy to update. But you should install it just after formatting your system & never disable it. As it is most popular anti-virus, most of the viruses firstly attack on avast files to stop its services. Not recommended if you cannot update virus-definitions regularly from internet.
Pros: Good Interface, Sandbox, Advanced Heuristic Detection.
Cons: No Protection against Phishing.
1. NORTON
Besides consuming some memory, norton is the best antivirus available. If you have norton, nothing can harm your system. Trusted by top industries & server administrators. Unlike most of the anti-viruses, it tries to repair files first. I am personally using its Norton 360 (Provides antivirus, firewall, identity protection, create backup, tune your PC etc.) & compared with Kaspersky, Bitdefender, avast, avg (Why the hell people use AVG??), Avira, Quickheal, f-secure, nod 32, zone alarm, trend micro, etc. No one healed my system files as Norton did.
Not recommended if you have RAM less than 1 GB & if you have version older than 2009.