I continually get questions about virus software. This person hates McAfee and another hates Norton, and still another hates MSE. There is no perfect virus software which is why I personally use MSE, Microsoft Security Essentials also called Windows Defender. I run the same thing on my kids computers. That combined with Google Chrome and a bit of cautiousness will reduce your likelihood of infection significantly.
That doesn’t mean you can’t pay for virus protection. I used McAfee for many years and never had a major problem.