"Email could not be delivered" - but was not sent by me!

From: Xylophone (m-rharrison_at_tiscali.co.uk)
Date: 09/27/04

Date: Mon, 27 Sep 2004 00:10:52 +0100

I have XP Home with IE6, with strong security settings in Internet Mode, the
latest Java plug-in and using ActiveX, and NAV2003, Outpost free firewall
(showing completely stealthed, but for one port closed), Adaware, Spybot,
Spyware Blaster, SpywareGuard, and I have renamed my admin account and
attached a password. So I try to stay secure. When running these programs
for problems, generally only NAV picks up and sorts a problem of any note -
Netsky and Swen are the most common, two or three times day in emails -yet I
keep getting, several times a day, a message from Postmaster or the like to
say 'could not deliver to,' then an email address is given, completely
unrecognisable by me, usually quite weird in its spelling, and never
repeated (I think).

Any comments/explanations/solutions to prevent???