Provide additional information such as copy / paste of error messages. Is
this an issue with a corrupt account? Did you delete and recreate the
account? What do you mean "cannot get to them"? Are they listed but won't
open? Are they not received during sync? With more detailed information,
maybe someone can help.
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.