My Win 8.1 system just started warning me that "Your Windows license expires on Wednesday, August 16, 2017" but when I look at System Properties, it shows "Windows Activation ----- Windows is activated" I'm guessing my system will lock up on Aug.16. How can I resolve this?

Background:
I have an HP Laptop with a Windows-OEM license. After recent tech support I had to re-install everything from the direct from Microsoft online downloadable copy of Windows 8.1. I thought all was well because System Properties seemed to show an activated license. Seems I was over optimistic.

When I try entering my OEM license key, the Activate Windows app rejects my OEM license key.