this maybe different, but i've tested almost every antivirus, and the result is that none of free antivirus-es could beat the payed ones. you may use any of them, but believe me, it's very risky if you are only depending on it (except there're not much activities around your computer such as connecting external storage device (flash disks, bluetooth, phone cable, etc.) and downloading. oh, even when you're in some chat room you might get some virus contained ads, right?).