You may be confusing the protocols. POP is a method of retrieving your mail, while almost all POP3 accounts rely on SMTP. You need to make sure that your SMTP settings are correct for your Bell CA account.
Try to make sure you enable SSL and use these instructions as a baseline. What I notice, most prominently, is that it looks like Bell CA requires SSL and authentication. That means under outgoing mail, or SMTP settings, you probably need to include your account details again. It looks like this was the last time they issued documentation for this:
http://support.bell.ca/Internet/Email/Windows-Live-Mail-2011-email-setup
I'm pulling up Windows Live Mail in a virtual machine to post some screen shots of where you need to go with this.