You guys are saying that I am the one that does not understand how a virus or an add-on works, and how you guys are saying Add-Ons can't run viruses. That is not what I was asking, I was asking whether viruses can HIDE IN the add-on files NOT if they can execute them (how do you get those two things confused). I know there are viruses that spread to any new files or certain types of files that are created, so I just want to be informed if I can get viruses from downloading add-ons so that I can get better protection like purchasing another firewall. (obviously badspot would remove them once he would find out but still...)