Long story short. I have a PC that i installed (generic, no activation) Windows 8 and installed the free Windows 8 media centre pack offer in 2012 and my windows 8 was activated after the installation. Later in 2013 I bought a retail Windows 8 key from MS store online but did not use that key and forgot all about it. I upgraded to Windows 10 a few days ago without changing my Windows 8.1 to that key. My question is without using that Windows 8 key, am I able to switch computer and able to keep Windows 10 after a year. Thanks in advance.