I use one called PC-Cillin. It is great. It has found viruses and it quarantines them or deletes them according to your own wishes.
It comes from
www.trend.com you get 30 days free trial but you can go way over. I bought it though, about £26 I think, and they are brilliant at letting you know of new viruses. It also works very well with Zone Alarm. Some don't like each other!