If you're looking for a free and easy to use anti-virus program than AVG Free is something you definitely want to look at. It's compact, yet powerful without being annoying and allows you to run everything in the background when you're not using your computer. The only downfall to AVG is that the Grisoft website is fairly difficult to navigate unless you know exactly what site to go to. Once you're there, however, finding and installing the software, you'll find that it's intuitive and will update itself if you let it, making it virtually maintenance free. Most times, when your virus scan runs it will bog down the entire system, but with AVG you can set the priority level so that you can continue to work while it works in the background. AVG has the advantage of being free and up to date on a daily basis, this puts it at the top of the list of software that I recommend. The small size of the company means that they can put more effort into being user friendly and easier to access over their pricey, bloated counter-parts.