Upgraded to Windows 10, then went back to Windows 8.1, no Norton

I upgraded to Windows 10, then made it go back to Windows 8.1 (Windows 10 is not ready for convertibles like my Yoga Pro).  I did nothing with Norton while in 10, but it would not start when Windows 8.1 was reinstalled.  I keep getting a message that another download manager is currently running.  I killed the downloader task and then uninstalled Norton 360 from the control panel, then tried the download process again (using Google Chrome) and got the same message about the download manager.  I tried rebooting and before running the downloader and got the same message again.  I ran the autodect app and it said there was no product found on my computer.  Any suggestions would be appreciated!

Jody