The following links may shed some light on the problem:

Understanding E-mail Spoofing
http://www.windowsecurity.com/articl...-Spoofing.html

Email "Spamming" and Email "Spoofing"
http://www.lse.ac.uk/itservices/help...g&spoofing.htm

E-mail spoofing - Definition
http://en.wikipedia.org/wiki/E-mail_spoofing

Nikki Peterson

wrote in message
...
I'm using outlook 2003 on a WinXp system. The other day I started
receiving massive amounts of undeliverable email messages that I never
sent. I've run AVG and TrendMicro and they aren't finding any viruses/
spyware. Does anyone know what it could possibly be? Thanks