I have norton. Doesnt block any ads - even the annoying ones. Shudnt be hard to disable though, if it does block ad's. Although I did build my computer, not get it from a company. And yes, by that you can infer that I installed norton of my own choice! Well, actually my dad's insistance. "If you didnt pay for it, it cant be worth having". Well thank you norton. My 4000+ 64 with 2GB or ram now takes 10 minutes to start up. And all so you can continually alert me about files which ARENT threats. Some day I will rebel and hit install. Someday soon.