"Windows Live Mail (being used now to post this item). "
Are you sure? As far as I know the only way to post on AB is by going to the web site using you browser.
If you are using the Windows Live Mail client then you can set it up using the same settings as for OE. If you want to receive ALL e-mails on Both machines, then you'll need to change the settings so that receiving an e-mail on one machine doesn't automatically delete it from the server.
In OE:
Tools
Accounts
Mail tab
Highlight account and click Properties
Advanced tab
Click "Leave a copy of messages on server" and set a suitable time period, depending on the frequency with which you check for mail.
Go through a similar process on the Windows Live Mail settings.