Windows 10: Win10 - product key obscured!

This may sound a bit absurd but having devoted nearly 2 days getting a new Win10 installation fully updated, I now cannot read the product key to activate the system.
The reason being that the 'MICROSOFT' security sticker covering the key has left a glue residue that's tougher than old boots. Apart from the first two blocks of characters it's impossible to uncover the remaining glue without destroying the key.
Microsoft refuse to engage in chat on the issue without the key. I believe this a genuine Microsoft product as it came in a security closed packet purchased for decent money from a reputable UK supplier.
Anyone else experienced this problem with MS products? Thanks for any advice.

:)

 

Win10 updated from Win8 - does clean install loose product key?

Use this option. With Internet connection, if asked for product key, click on "Skip This Step" or "I don't have a product Key". Windows will be activated automatically.

 

Need product key for Win10 re-load

• Hi, I had to do a factory reset on my Toshiba laptop (multiple problems, black screening, etc.). I downloaded Win10 from MS site and have loaded it back on but product key required. I have no product key because the previous install was free upgrade from
  Win7 a few years ago.

 

Cannot upgrade to Windows 10 - Unique Product Key situation

No... let me try again.

• Old computer is running Win7 Pro (SP1) with a Product key I have from a few years ago. The Product is activated already, but I do NOT use this computer at this point, so I didn't worry about using the Product key when moving to the new computer (see below).
  
• New computer is running Win10 Pro, with data and OS migrated from the Old computer, (same Product key as above), then Upgraded to Win10 (without getting a new Product Key).

What I am trying to do now...

• I want to upgrade the OLD computer (Win7 Pro) to Windows 10... using a new Product Key I just purchased.
• I have tried to do this internally, and also using the ISO burned to a thumb drive. But it does not want to work.
• Steps:
  • Start from USB drive.
  • Enter New Product Key (or click "I don't have one").
  • Install initiates and then tells me to restart from Windows and then open the installer again to continue.
    • At this point, I actually need to Quit the installation to restart the machine.
  • When restarted, I go to the USB drive and restart/resume the installation process.
  • I have tried to download and not to download updates, but when the installation fails, I see the message, "Something happened" and "Setup has failed to validate the product key".
  • NOTE This happens if I enter the NEW Windows 10 Product Key, or if I skip that step (which I assume means that it will use the old Windows 7 Key for the upgrade).