I'm feeling frustated! I want to help you but I can't quite see exactly what problem you're experiencing. You say that you can use the internet, so I assume that you mean you can go online and use your browser to visit different websites. If this is the case then your modem isn't the cause of your problems.
Please explain: When you're trying to access your e-mail (or newsgroups) at what point do things go wrong? Is it that Outlook Express won't load onto your screen or that you can't get it to send/receive your messages? Is this something new or have you never been able to get Outlook Express to work?
Please provide more information and I'll be happy to suggest a solution.
Chris