TO WHOM IT MIGHT CONCERN:
I searched Norton forum and this happened once before in 2008 to someone. I received an attachment from a questionable source which was deleted before reading. The E-MAIL BOMB went off anyway within 24 hours. It was very soficated and Norton Anti-virus 360 did not detect and maybe complicit in the design of virus. The virus deleted junkmail inbox and deleted files in Outlook 2007. Maybe work of secret government program. Norton 360 got stuck on WSUSSCN2.CAB until hooked-up to internet in which Norton 360 said all is fine.