Outlook Express.

Outlook Express emails keep going missing. I have one account on my laptop.
Companies that I work for send emails and I dont receive them and they are
not returned to them. When I am on outlook express I receive email, but
email that is sent to me when offline do not come in when online. My
connection on Internet
Explorer is Broadband but when I am on Outlook Express sending or
receiving it say the connection is Local Area Network but when I try and
change it to Broadband Connection to match the Internet Explorer it does
not work at all. I have Wireless Connection with Wanadoo and they were
unable to help and told me to contact Dell support. I have Windows XP