Guys,
Maybe I'm nuts but, I don't have any of those Anti-??!!! installed and my Daw runs really fast and stable... Many people say that my computer is full of crap if I don't have those things installed and my answer is it' is working just fine and most of the computers that have those things installed, are really slow.
But I have something to protect me, of course. Periodicly when I'm sure that the system is going smooth I back it up with norton ghost so, if any of those virus start messing with it, I can always get back to a point where it was rolling OK.