Virus

A computer virus is sending out emails from me – don’t open if you get one.

I am puzzled how this happened, as I have not received or opened any suspicious emails today or visited any dubious websites. I have Norton on fully and it automatically both updated and scanned last night. As soon as I started getting back a rash of auto-replies, I started scan again and it has immediately detecting and started eliminating threats.

I am not the most technology savvy of people – does anyone know how this can happen without an apparent triggering event such as opening an infected email?