A few years ago we did a pretty extensive test of different AV apps at our institute. The Norton AVs (and a couple of others too) would allow in an old floppy boot sector virus (and floppies were pretty much on the way out already by then!) and never saw the nasty beastie, which infected loads of stuff on the HDDs, even at the full protection settings. We really decided to permanently nuke Norton AV from our shortlist (without the possibility of a future parole) when we looked up the virus (as identified by a better AV app) in their own online database. Turns out it was specifically listed as detected and cleaned by it...
