Might give this a shot:

http://www.greenmtngeek.com/2008/06/wordpress-not-sending-email-try-this-fix/

Hi, I did some searching,and found the trac ticket for this issue.  In the track ticket, we are instructed to remove this line: $phpmailer->Sender  However, that line was nowhere to be found in the file it told me to remove it from: wp-includes/pluggable.php.  I believe the no sender plugin didn't work because there's no "$phpmailer->Sender" line.  I'm using wp version 2.6.2.  Should I submit another track ticket?  Thanks!!

Hi, I've upgraded each release, (accept the small update releases,) (but I had to reinstall wordpress anyway, so I thought I'd upgrade to 2.6.2.  Anyway, haven't had comment notification since like 2.3, , 2.5 didn't fix it, and neither did 2.6.  I guess the question is if that "sender" line is absent, (and I looked twice,) once in dreamweaver and once in the Cpanel file editing window, then why is it not working?  Thanks!

I have 2 wordpress installs, one is on a subdomain, and one is on the root public_html directory, (that's my personal blog.)  I haven't tried the SMTP plugin.

since wordpress uses the php mail function as a default, sometimes when you have an installation in a subdomain, it can't find the path to send mail. Assuming there are no plugin conflicts, we can use SMTP to deliver the comment notification. I wrote a quick plugin you will have to modify manually with your smtp settings. The SMTP plugin I recommended rewrites the entire wp_mail function. My plugin only overrides the default method of sending with SMTP with authentication. You need to enter:
your mailserver name (usually mail.yourdomain.com);
a mail account username (you@yourdomain.com);
the password for that account;

I tested my plugin on my blog and it seemed to work fine. If this doesn't work, your problem is not email related but some other plugin which is interfering with the comment notification problem.

OK, both of those smtp mail plugins didn't work, but I've never used smtp before.  I did put in the username and password to the email account I set up for wordpress, (which is just wordpress@lifes-adventures.net), and I set the mail server as mail.lifes-adventures.net.  Is there anything I missed?  Could it be a server configuration issue?  Besides the 2 smtp plugins, (I deactivated the other one before I activated yours,) (should I have kept it active?)  The only plugin I have installed right now is akismet.  Thanks!

Hi, yep I did, at the time I created it, I was installing the no sender plugin, the instructions said that if the plugin didn't work, that's what I needed to do.