Can't send email with attachments in Outlook 2007

[John D. Bell]

I recently installed outlook 2007 (rtm) on vista and I can send message with
no attachments but not with attachments.
Outlook just seems to ignore the messages with attachments and they stay in
the outbox.

If I use Windows Mail it all works fine. I did have AVG AntiVirus 7.5 and
wondered if that was the problem, so I uninstalled it but it made no
difference.

My settings are fine because I can send messages without attachments.

Does anyone have any ideas?

thanks in advance,
John.