The best way to keep from getting a virus on your computer is to make sure you have all the latest updates for your operating system and security software. I teach embroidery software classes and have seen so many people hit the "remind me later" button when their computer wants to update.
Also, Microsoft now has a security software called Microsoft Security Essentials. It works on 7, Vista, and XP. It is free, but it really works. I have it on all the work computers. I had it on my laptop for about a year before I did that.
I always update when my computer says it has updates. I make sure my virus software is always current. I have never had a virus. I have had a personal computer for 28 years.
Do those updates when they are available, not later.