Keep everything updated. Running your preferred antivirus/firewall. Last but probably most important, use common sense and be alert of what you install. In most cases virus/malware is self inflected by clicking - OK, install, etc.. opening a link or an email, downloading warez and cracks, surfing porn and installing things from porn sites.
Filter all ads analytics and tracking domains with TMG 2010 at the edge of my network. Scan downloads first with TMG as they enter the network and second with Eset (Endpoint or File Security) Lock down computers and servers with group policy Use vlans to segregate trusted and untrusted networks Use Eset Endpoint Security on all clients & Eset File Security for windows server/core
Don't you just love the ones who have virus/malware problems, and then you find a veritable mountain of security software installed. And all of it conflicting, out-of-date, and/or disabled.
Ah, sorry, but for some reason I couldn't edit my previous post.... I was going to say that personally I use Windows Defender and Malware-Bytes. Spy-bot and C-Cleaner also put in an appearance when/if required. Before I started playing with Win 8, I used Avira for many years.
Linux System, no antivirus, properly configured firewall, use trusted software. Easy to trust open source as you know what is in it. Windows system No Real time protection Disabled Action Center Windows Firewall on Windows Updates current MRT Scan every month (never found anything) MSE / Windows Defender (in w8) every 6 months (never found anything) Know what I install and install only what I need. Since I use Windows just for Visual Studio and Office and a couple of old games, I don't get infected.
As for viruses from the web for firefox I use NoScript will avoid websites into ur machine and as we know we are being watched 24/7 by google analyst scripts analyzing what we do and compiling into a database which is nuts and only Panda Cloud Free for anti virus since it puts the load on the cloud which is run by like 1,000 quad x6 xenon rigs (12 threads each with hyperthreading) So that's 48 threads per rig running at say 3Ghz per thread putting out like 144,000Ghz of powerhouse performance so I can enjoy all the performance of my 4.2Ghz core i7 rig since all others and I mean ALL others put all the load on the cpu/ hard drives/ memory so they rob you of computing power. =)