Windows 8.1 activation

Hi everyone,
I have just formatted my laptop and installed a new version of Windows 8.1,
At the beginning it was all ok, but after some hour it started saying that it's not a genuine version and that I need a product key.
Initially I had a genuine Windows 8 on my laptop, is there any way to rescue my product key?
Could you tell me what to do otherwise? I also read some things about cracks like KSMPico but I never used anything like that so I've no idea what to do with those.. I plan on upgrading to Windows 10 soon anyway, so I wouldn't mind getting something temporary.

Thank you very much!

this utility will show you your OEM key and what version of Windows 8.1 its for. Showkey - Windows 10 Forums You don't really need to know what the key is, just what version was installed at the factory. Once you know what version you need go here, Create installation media for Windows 8.1 - Windows Help and download it. If you install the correct version it will automatically use your OEM embedded key without you having to type it in. Just so you know talking about cracks and cheating activation will get you banned in the blink of an eye. You might want to edit any such reference out of your post.
http://www.eightforums.com/tutorials/18309-windows-8-windows-8-1-iso-download-create.html
http://www.eightforums.com/tutorials/15458-uefi-bootable-usb-flash-drive-create-windows.html
http://www.eightforums.com/tutorial...e-firmware-interface-install-windows-8-a.html
http://www.eightforums.com/tutorials/2299-clean-install-windows-8-a.html

you need to be sure the edition of windows 8.1 you install(ed) matches the edition of windows 8 that came with your PC

core 8 to core 8.1
pro 8 to pro 8.1
single language 8 to single language 8.1

if this is correct - then the windows 8 key will activate the windows 8.1 OS

you can download the official windows 8.1 media > Create installation media for Windows 8.1 - Windows Help