I have used Kaspersky for 2 years now. I also use this at the Office. I have also used McAfee and avast. McAfee was not able to pick some antivirus and I suffered a lot from system crashes. I then changed over to Avast which was much better in networks attacks rather than file protection better than Mcafee but still I suffered. I tried Kaspersky for windows workstations and upto now,from 2007 my system has never crashed or attacked online! So I stuck to it/ Now, what determines the antivirus to use?