Up until the 2006 edition, Norton Antivirus and Internet Security were accessible for blind people and other users of screen-readers. However, since then, accessibility features have been completely removed.
In the beta of Norton 2012, it seems to be possible to navigate the UI using the keyboard. All that would be needed now is to make the buttons and various descriptive texts distinguishable for screen-readers - the one I use is JAWS For Windows 12, which is one of the most popular and widely used.
In my opinion and apparently those of many professionals, Norton is the best security one can buy. However, blind people have to settle for a less effective option as the best one isn't accessible.
I really hope that accessibility can be added in a not too distant future version - I will post this in the public beta forum as well.