Windows 10: Windows 10 Pro activation - COA sticker doesn't have product key

I'm trying to activate Windows 10 Pro on a refurbished HP Z420. There is what appears to be an authentic COA sticker on the top of the box. There is no indication of the usual 25-digit product key, but there is a 23 digit number along the top of one of the UPCs exhibiting a format I'm not familiar with as well as a 10-digit number, indicated by the words "Security Code:" near the lower part of the sticker. Does anybody know how I can validate the software with the information on the sticker? I bought the computer from one of probably 8 or 9 vendors, I don't remember which.

:)

 

Windows 10 Pro COA or Product Key

I purchased a laptop from a Microsoft Reseller. It has Windows 10 installed. I can find a 20 alpha numeric product key on the system page but there is no COA sticker anywhere on the unit. I want to upgrade the hard drive to a larger size but am afraid
that the Windows 10 Pro software may not re-install without a 25 digit COA. Is my concern vaild? Is the Product Key the same as the COA???

 

Activation of Windows 10 Pro doesn´t work

Hallo, i can´t activate my windows 10 Pro (free upgrade from windows 7);

Info: 0xC0EA000A

Manual activation doesn´t work either.

Important (i think): I had to re-install windows 10 (3 or even 4 times). because I had massive problems with "Start and Cortana Issues".

I hope, I don´t have to search the old product key.

PS. Yes, Windows 7 was genuine.

 

windows 10 activation no product key

If it says it will expire, it might be a KMS activated installation which requires access to a business network.

Click Start > Settings > Update & security > Activation

Which edition is listed as installed, Home or Pro?

Check if there is a COA (Certificate of Authenticity) sticker attached to the laptop at the bottom or in the battery compartment.

If there is one for Windows 7, you could try using that product key.

• Windows 7 Starter, Home Basic, Home Premium, Windows 8.0 Core, Windows 8.1 Core
  will install Windows 10 Home
• Windows 7 Professional, Windows 7 Ultimate, Windows 8.0 Pro, Windows 8.1 Pro
  will install Windows 10 Pro
  
  

If you have a matching key, then click Change product key then try entering it.