Question : Outlook can't connect to incoming mail server - but can ping it - what setting am I missing?

I have an employee whose pop account can be set up in outlook on other computers in the same building, but can't be set up on her computer.  It says that it can't connect to the incoming mail server or the outgoing mail server.  Now, I can ping the mail servers from her computer, as I can from all the rest, and I have set up her account on other computers, but on the one she works from, no luck.  What am I missing?  I should mention, we have an exchange mailbox for everyone that the messages are stored to.  However, we have a separate mail service online that actually manages our email accounts.  The mail is sent there first, then outlook downloads it to the exchange server, then uploads from the exchange server into outlook for viewing.  It is a convulted setup I inherited, and I'm a little green on Microsoft Exchange, so I don't feel comfortable making any major changes, especially since anything new tends to frighten those just using the computer to do their work.  So, with that said, any ideas why I can set up her account in outlook at other computers, just not hers?

Answer : Outlook can't connect to incoming mail server - but can ping it - what setting am I missing?

Sorry, I don't see anywhere in your original post that you could log onto the problematic machine with a different account and have mail work.  Assuming that's the case, it makes a machine-wide firewall less likely the cause.

Still, knowing whether you can successfully telnet to the server on the specific ports using her account on her machine will be useful information.  If you cannot, then there is something blocking the ports - even if only under her login.  If the telnet tests work, then a firewall can probably be eliminated.  

While it's possible Outlook could be the problem (I assume you have completely deleted and rebuilt her POP account on the machine in question), the other thing that comes to my mind is a local virus scanner installed with some type of personal antivirus product.  These products interpose themselves between Outlook and the server, creating a mail proxy through which SMTP and POP traffic must pass - essentially they intercept traffic on these ports.