Outlook email receive problems - Client email information

Here is my clients email information that you requested. They can send but cannot receive emails through Outlook 2007. The outgoing port is 587. See incoming below.

Email/s address affected:smiles@westlakedentalcare.com
drnaylor@westlakedentalcare.com
info@westlakedentalcare.com
newpatient@westlakedentalcare.com
ISP(Internet Service Provider): Earthlink
Security Software used on the computer: Nortons antivirus
Operating System (type "winver" in the run or search bar after hitting the "Start" button): windows 7 professional
Email software(include version): Outlook 2007
When the problem started: April 14 2013
Action taken: Changed incoming port from 110 to 995. did not work.

I need a list of step to give to my client to try.