NS disappeared, will not reinstall

NS has disappeared form one of my PC's and the reinstall has been "running" for hours.

My current 5-device NS key has 104 days remaining.

I have 3 Win10 PC's that recently received the update to 1607 14393.953. 2 are working fine; the problem on the 3rd (the only AMD system FWIW) may be related to that update.

The fix tool didn't find NS. The uninstall/reinstall tool didn't find a valid key and asked for a new one. So I went to programs and features to uninstall, thinking I would just reinstall manually.

Multiple restarts haven't helped.

I attempted a system restore to 12Mar2017 but that failed. I have a recovery USB drive created Dec2016 to try as a last resort.

There are no apparent problems with any other apps.

P&F shows NS 22.9.1.12 (I guess it's too much to ask for a Help>About in the app?)

That's all the pertinent info I can think of - any ideas?

Thanks...

Try logging into your Norton Account at   https://manage.norton.com

Click on My Norton at the top right of the screen, then click on My Services. Find your current subscription. Click on the Download button and follow the instructions to install a pre activated copy of your Norton product. No key required. Be sure you run LiveUpdate manually a few times, restarting as necessary, until no updates are available.
 

FWIW   Help About is in the app.

help abour.jpg