Problems with receiving email

[Erin Pautler]

I began working for this company at the start of the
summer (I am an intern here) and since I seem to know some
things about computers it has been my job to fix all the
technical problems we have been having.
When I arrived here in May 2003 all 8 people in the office
were using the same email account. I have since set-up a
website for the company and given them each their own
email accounts, but since the company has widely
distributed the first email address, it is the one that is
primarily used.
Anyway, the problem is: some people receive some email
while not receiving other email and some people have no
problems at all. Each person is accessing the same account
from Outlook Express on different computers and I have
already tried removing the address from all the computers
and re-adding it. I also have tried making sure everyone
had the box clicked "keep a copy of message on server."
Nothing has seemed to work completely. One person in the
office will receive a message from customer "A" and
another person won't, but will receive a message from
customer "B" while the first person did not.

Any ideas? (Sorry this was so long by the way).
Thanks!