Personally since I dont trust any single anti-virus program, i just have a bunch of programs to protect against unwanted files...so usually when i notice something wrong in performance or something i just scan my comp with spybot, Ad-Aware, AVG personal edition, and PC-Cillin and usually all of them find something that another didnt, even when all are kept updated. Currently im trying out NOD32 and soon AVG enterprise......so my philosophy when dealing with viruses and adware and such is: You see a bug, get a bazooka
Also, i have McAfee on my comp (installed by a previous owner with a password that i dont know so i cant take it off of super-paranoid mode) and so far its been more of an annoyance than a help....so im thinking of just trashing it....but then again....its on my comp for free so i dont know