Activation problem

[mike21]

I am having problems with updates. A feature update failed so I ran the update trouble shooter and tried again – the update again failed to install but this time I got a pop-up which indicated that I did not have a licence and that I should buy a copy of windows 10 – first of all, was this because updates cannot be installed on an unlicensed machine. My desktop is about 12 years old and had a valid licence for Windows 7; it was upgraded to Windows 10 many years ago. I ran Belarc Adviser and it listed my licence key. I can re-enter the key in settings but I am concerned that doing that might lead to use of my computer may be blocked if, due to some corruption, the product key is not recognised, I still have the Windows 7 key sticker, but that key string is different to the Windows 10 key shown on Belarc Adviser

. Presently my computer works but boot up is much slower and I keep having attempts to download the update. What should I do – I have attached a couple of screen shots.