Window 10 product key on a refurbished PC

[eandg]

I recently purchased a refurbished HP Desktop from Walmart.. After startup I encountered "activate Window"   The person I showing at the bottom right hand corner all the time. I need the Window 10 product key to active the window. My problem is, I can only get  the 3 group of the product keys while the first 2 groups covered by a sticker with Microsoft water mark.  What should I do to find out the product key.  Can you help please? 

Please copy the answer to my email too because I experience 2 times disconnect from  this community before I can finish this request.  

[TheOldMan]

That model came with Windows 7 or Vista.  If it was not upgrade properly from Windows 7 to Windows 10, then it probably will not activate on its own.  There will be no Windows 10 product key.

I would get with WalMart to have them rectify the problem as they are the ones selling an improper upgrade.

[eandg]

Thank you. It really help but issue not solved. 

[TheOldMan]

Did you have a chat with Walmart about it?  They are the reseller and should give you help.  If they do not, then you will need to purchase a new product key for Windows 10 or reinstall Windows 7 and then upgrade it the proper way, if that upgrade path is still available.  The actual free upgrade has ended long ago (years) but I have read where it was still possible.