No, they aren't coming from my PC. They are being sent by a robot that is spoofing my address as the sender. The robot is picking sequentially named recipients, most of which bounce as underliverable. I get the notice they can't be delivered .

I run Norton every day. The only long term fix is to change my email address. I really don't want to do that. Just hope the sender eventually gives up. Maybe there should be a charge to send email???