Patty,
I noticed that you joined in on another post and made a similar comment about not being able to send.
Whether you can use the "business" server depends on whether they can supply you with a "standard format" server name such as smtp.isp.com, not just the IP number.
Avast depends wholly on the manner in which the email client is configured to direct email to Avast, and the server format name is crucial to accomplishing this.
When you specify the IP number, you inadvertantly restrict Avast to that domain. This is the reason that AVAST seemed to work just fine when you used your own ISP information.
Also, keep in mind, that from your description, you had "authentication set to off" which means the Avast format should be only #smtp.isp.com or #pop.isp.com
I would recommend uninstalling Avast, leaving authentication on, then reinstalling Avast. This time, Avast will see the authentication on, and you can use the more common format "username (or full email address)#smtp.isp.com" or similar for POP
Avast has a network version for use in such applications (or desires) as you mention which works as you would want it too (using IP numer), but unfortunately it is not "freeware".
Good luck.