...
Help for you before you format, get a different AV program, Norton bites, all their products could pretty much be called proprietary, I myself do not use AV, I have no need for it, I can tell the difference between funnystuff.exe or funnystuff.bat rather than funnystuff.doc or funnystuff.jpg
As for stopping a file before it is opened, yeah...I guess it works, but if you didn't get the file off of the email to begin with...why would you open it?
That's just my opinion, if AV makes you feel safer, go ahead and use it, to me, it just causes lag when I play games online, and takes up System Resources...