ppoe is used if your isp requires a password, like dsl (sbc, att). I did not read the whole thread, so forgive me if any redundant questions are asked. If all you are trying to do is RDP, then once you have port 3389 forwarded in your router to your computer's internal IP address (double check to make sure your internal IP for your computer has not changed), right click on "Computer" select properties, then click on Advanced system settings> then click the remote tab, and select the option you want (I use the second one) from the remote section. As far as dyndns, I use
www.dyndns.com to get a free dyndns name (zay.selfip.com). Hope this helps