Which Antivirus Software do you use ? Why?

Anti-virus Software's are much essential programs of every Windows PC these days. Surfing online without an updated anti-virus program is like inviting viruses, adwares and Malwares, which harms your pc.Here are some best anti-virus programs . So Guys, Which of these Antivirus Software do you use ? Why?

we are using Norton 360 because i think its best compare to any other.

I am using Mcafee. This software is very powerful because it goes through all the places in your computer CD-ROM, floppy, network, compressed files. It can recognize many viruses, to check the downloaded files, e-mail, Internet, etc.. The problem with viruses is that they can go through the disks, networks, bulletin boards, e-mail and Internet.