Avast! ....Norton was send to Mars...Kaspersky,no,no,Panda what a nag....and intolerant ,quite like Avira but for newbies and free....Avast....by a mile....Zone Alarm,and a few free anti spy ware prog....had Norton for a year, what a joke Zone Alarm and Avast have been working quite well,side by side(some problems have been reported ,so far so good)....