Ann, after you uninstall McAfee, download and install the free Avast antivirus:
http://www.avast.com/eng/download-avast-home.html

Be sure to configure it to do no mail scanning.
For more on the reasoning behind this see
http://www.oehelp.com/OETips.aspx#3

Gary VanderMolen

It looks like you're set up to use port 0, which is seldom the correct port
for email.  Check your internet provider's instructions for the correct port
number.

The Port 0 error is indicative of current or recent antivirus corruption.

The exact same error as what?  Many of who answer frequently here
are using Windows Mail to read the newsgroup, and don't have a
good way to go back to previous messages in the thread.

The error number is often not enough for us to give much information.
If you need more help, right click on the message and copy all of it
to your next message.

Which Symantec antivirus program?  Most of those with the Norton
brand name tend to cause enough problems in Windows Mail that
they need to be uninstalled, then have this cleanup program run to
take care of what the uninstall left behind:

<http://service1.symantec.com/SUPPORT/tsgeninfo.nsf/docid/2005033108162039>

You may then need to remove your email program, then restart
Windows Mail and add the account again.  We haven't heard
enough about Symantec antivirus programs without the Norton
brand name to make it clear if this also applies to them.

For the message you can't delete, download and install this
hotfix, with Windows Mail not running:

<http://service1.symantec.com/SUPPORT/tsgeninfo.nsf/docid/2005033108162039>

Although it's labelled as for mail stuck in the Outbox, it also works
in other folders.  If you don't know whether you have a 32-bit version
of Vista or a 64-bit version, try the hotfix for the 32-bit version first.
The Vista SP1 update contains this hotfix and more, but takes longer
to install.

If this solves your problems, you may want a replacement antivirus
program that doesn't cause such problems.  Most versions of the
McAfee antivirus program and a recent version of the Trend
antivirus program are bad choices; they cause problems in Windows
Mail too.  I recommend either avast! or AVG, either one with a
custom install that tells it to leave out the part that scans email.

http://www.avast.com/eng/avast_4_home.html

http://free.grisoft.com/ww.download?prd=afe