Are you using a non-compatible antivirus?
Windows Mail is not compatible with most McAfee
or Norton security programs. Those will need to be
uninstalled, not just disabled.
Even compatible antivirus programs will need to have their
email scanning option turned off. For more on this topic see http://www.oehelp.com/OETips.aspx#3
Does the mail not come in?
Does it not have the paperclip?
What anti-virus?
Email scanning should be turned off in any anti-virus. Also exclude EML
files from the scan. It provides no
protection not provided by the regular resident protection.
Besides that, McAfee and Norton are not compatible with Windows Mail and
Outlook Express and should be uninstalled.