sends some but not emails

[robert4]

I can send messages to hotmail accounts and to a few (very few) people, but
most never receive my emails. I have tried disabling norton but that
doesn't seem to help. When sending to hotmail acounts they get the
messages within 30 seconds, but messages sent to people outside hotmail
will NEVER get them. I have 'send immediately' checked and it says it is
sending, but it never goes anywhere.

I am using Outlook 2003 with XP sp1. I also have Norton Internet Security
with Norton Antivirus. Any help would be greatly appreciated.

thanks