Some of the spam I received results in a message that reads (I use Norton Antispam): "The e-mail address "my-email address here is shown here" already exists in your allowed list. In the from address of the e-mail it will give a random name such a "Timothy Cameron [my-email address is shown here]" I get a few of these everyday and at first I thought that my computer had been contaminated with something that was sending out spam without my knowing; sometimes I will also get a reply from someone else saying that the message I sent (always a typical spam message) was rejected.
My thought has always been that my computer is secretly sending out spam but I don't know how this could be happening? I do have a cable connection and my computer is always on but I also have a secure firewall, use AdAware, PestPatrol, Norton Anti-Virus, have looked up to see that everything in my start-up are programs that should be there, etc. Backweb, Backweb Lite, SpyGame Arcade are the only things I ignore and don't delete (although I have 3 Kontiki DLL files which say they will delete on next boot but don't). I've also run other security software and still have come up with nothing to explain this.
Why am I receiving both occasional spam e-mails to myself (sent to me) with an alias and my own return e-mail address as well as occasional spam e-mails rejection messages from others which appear as if my computer has been sending spam? Why can't I find any clues to this behavior and lastly, why when I look in my e-mail sent folder (by the way I use Outlook), don't I see any "sent" messages that should have resulted in these messages that seem to be going out?