sender spam eller ej

Jeg får fortiden nogle "mails retur" som jeg ikke selv har sendt. de lyder henaf:
Spam detection software, running on the system "av-mx.acomma.com", has
identified this incoming email as possible spam.  The original message
has been attached to this so you can view it (if it isn't spam) or block
similar future email.  If you have any questions, see
the administrator of that system for details.

Content preview:  alt URI:http://www.networkthree.com/index-ambien.gif
  alt URI:http://www.networkthree.com/index-levitra.gif alt
  URI:http://www.networkthree.com/index-phentermine.gif
  URI:http://www.markandsave.com/info Buy Levitra on the Internet
  URI:http://www.networkthree.com/order.gif [...]

Content analysis details:  (5.8 points, 5.0 required)


OG

This is a delivery status notification from gcbomail.ngdc.net,
running the Courier mail server, version 0.45.4.

The original message was received on Mon, 07 Jun 2004 00:04:56 +0200
from mail.broendbybredbaand.dk ([::ffff:217.116.244.247])

---------------------------------------------------------------------------

                          UNDELIVERABLE MAIL

Your message to the following recipients cannot be delivered:

<blalalalalaa@hotmail.com>:
    mx3.hotmail.com [64.4.50.239]:
>>> RCPT TO:<blalalalalaa@hotmail.com>
<<< 550 Requested action not taken: mailbox unavailable


Nu er mit spg. ER det mig der sender dem? eller er det bare nogle der sender dem ud for at jeg skal tro min computer er usikker?

Jeg kører med fuldt opdateret
- Agnitum Outpost Firewall 2.1 Pro (Block Most mode)
- Norton AV 2004
- AVG 6.0
Har desuden også kørt hijackthis og finder intet underligt i loggen.