No need to bow out, and I think we all understand the frustration. I too had my ISP change on me one day and suddenly I could not have anyone connect to me. Fortunately I was familiar enough with the forums to understand that my ISP switch on "
Advanced Security" feature for me without telling me. This feature they implemented to protect me was intentionally blocking other computer from connecting to my network. Worked one day, didn't work the next. Had I not known about the possibility, I would have been stuck and more frustrated than I was (and for much longer than the 30 minutes it took me to resolve).
If their is value and something we can help with, please let us know. FYI, the point of my post was to reassure you that you were not wrong, and that unfortunately in today's world, their is no perfect solution for connecting multiple computer together across the world when you can't control all the networks in between!