Windows 10: Activation Windows with key or activator, what's the difference?

I will use license, but some people say to use activator, so I wonder what people lose when they play in "Pirates of the Caribbean"
I had Windows 7 Basic with license key on my PC, I upgraded to Windows 10 as was offered, and now my Windows is license? So now I want to install Windows 10 on SSD, but how, now I can't use same license and will buy, I lost old pc case

:)

 

activate windows 7 oem key

There is no difference between the OEM disc and the Retail disc with Windows 7. A retail disc will accept a OEM or Retail key, and vise versa.

If the OEM Key wasn't going to work with the disc you have, it would have stopped you during the install when it first asked you for the key, not during activation.

What is likely the problem is that, since the OEM version has already been activated once, it is failing activation again. Activate it over the phone using the option given to you on the failed activation screen, and you shouldn't have a problem activating it.

 

Windows 8.1 pro + WMC key activation

So it will be fine installing 8.1 pro with a KMS key, then switch to my 8 pro key and it will activate ok?

Maybe a daft question but why can't you just install 8.1 pro with the 8 pro key, or is it different keys for 8 and 8.1? seems silly when 8.1 is a free update anyway.

 

windows 8 activation key

You can use a Windows key as many time as you want provided it's only on one computer at a time. If the automated activation fails, just call the number it provides. Six minutes later, you're activated again. If it asks you how many computers it's on, just say "one" and you're golden.