I see you posted with a Yahoo email address. Is that the email account
you have set up in Windows Mail, and if so, is it a free account?
US-based free Yahoo accounts have webmail access only, no POP
access. Windows Mail handles POP mail but not Yahoo webmail.
Yahoo's solution is to pay them for premium "Mail Plus" service:
http://help.yahoo.com/l/us/yahoo/mail/original/mailplus/overview/index.html
and use the special settings for that service:
http://help.yahoo.com/l/us/yahoo/mail/original/mailplus/pop/pop-14.html
If you are OK with using a non-Yahoo email address, you have these other
solutions that will work with Windows Mail:
* Use the email address assigned to you by your ISP.
* Use a free Gmail, AOL, or Hotmail/Live account.
You can also continue to use Yahoo's webmail:
http://mail.yahoo.com
If you need more help with any of these solutions, just ask.