All the MS virus guys want to go after Linux and Android. The truth is that these things are probably 10 times more secure than a standard Windows setup. Nearly all Linux and Android exploits involve carefully downloading a bad program, or a tailored attack on a major target. As opposed to Windows, where a simple click is sufficient.
I tell everybody that if you have Windows use Chrome or Firefox, and never use Outlook. Nobody listens. Every company that has executives using Windows at airports and such, are susceptible to Sony-type attacks, but they take a lot of genius time, so maybe you'll be spared. Have fun!
Clarification: No matter what sort of virus screener you have, the Windows - IE - Outlook combination is still susceptible to the 'new trick', after, like, 30 years. Mix it up a little and you are better off.