Before you take any drastic steps, shut down the computer, reboot the modem, and restart the computer. For my modem, the procedure is to unplug the modem for about 30 seconds, plug it in again, and then wait for all the lights to be steady. This can take a few minutes, so be patient. In my case, it turns out that the modem was not at fault (Time Warner exchanged it several times) but there was something else on the line that needed fixing. Rebooting the modem, as above, was a temporary fix only.
As to your other questions, you can go all the way from Mavericks to Sierra without installing intermediate OSs. When you download Sierra from App Store, you get the latest version, not the original. (Actually, I'm not sure of that, but if you get the original it's easy enough to update via App Store.) I can't answer your question about doing a clean install.
Last edited by jchuzi; 04/02/17 06:39 PM.
