W10 verified

[Windows Central Question]

Hi. I have a Lenovo laptop L420 several years old. Was updated free from W7 Pro to W10 Pro.
Switched on this evening and I'm not verified, or "Windows isn't Activated. Activate Windows now".

Also I saw some screen saying Activate Windows Home or purchase Windows Pro, (I think).

I'm rusty on what I knew and remember about Windows in general. This is my 4th pc since 2002.
Thought a Windows sticker would be on the casing.

Is this a known temporary issue with Windows?

My Settings - About says I have version 1809 installed on 3rd October 2018.

I would like to get an opinion before I get into it and get irretrievably stuck. I had some paperwork I will search for, but I'm sure it's only glossy folding manuals.

Sorry if this is a regular question with a posted answer. I did a quick search here and saw a guide for retrieving a product key by entering code or something.

 

[me just saying]

what happens when you actually try to activate. Where did you get your win10?