Five free tools to keep your Windows PC running malware-free | TechRepublic.
I like Tech Republic; their contributors have good information delivered in a timely fashion. This article is a little dated (it’s a year old) but the anti-malware products are still relevant.
I personally use Microsoft Security Essentials and have been predominantly malware-free since it first came out. However, nothing is completely foolproof. That’s why I keep MalwareBytes installed (though disabled) for deep scans when something seems “odd” with the system. I also have ComboFix sitting in an archive that I can access in “safe mode” should the need arise (I haven’t had to use it yet, knock wood). I have used both Avast and AVG (free versions) and consider them acceptable, though I believe MS SE does a better job for me. Your results may differ.