I looked at your question some time ago and carried out similar web searches to those done by Fern57. I found the same information as he got plus some detailed technical stuff which gave lots of explanations but no solutions!
Since then, I've had time to try to think what I might do. Since SMTP settings are specific to each e-mail account, I suggest re-creating the account within your e-mail client. (You'll need to know things like the POP3 and SMTP info but you can get these from your ISP/e-mail website. You can also copy them from the 'Properties' section of your existing account as long as you're 100% certain that they are correct!).
Assuming that you're using Internet Explorer, go to Tools, then Accounts, then Add, then Mail. If your existing e-mail account is known as 'myemail' then choose 'myemail2' as the name for the new account, Then keep clicking 'Next' while filling in the correct details for your e-mail account . Then try to receive e-mails via 'myemail2'. If this works, just delete 'myemail' and rename 'myemail2', deleting the '2'.
If that doesn't work, you can be fairly sure that your problem has nothing to do with the configuration of your e-mail client. At that point it will be time to try another question on AB!
Good luck!
Chris