Sendin mpegs by outlook

Something has crawled into my pc and occassonally when i send mpegs by email using microsoft outlook. it just keeps sending it over and over again until I disconnect. With unlimited broadband it just keeps going and the last one was a 2meg clip that went 15 times. needless to say the recipients are getting the hump especially those on 56k dial-up.

Any ideas, a full spyware and antivirus scan and adaware and ccleaner check reveals nothing. I have doen the full clean up process suggested elsewhere.

I'm on Windows XP

Thanks in advance

Jono