Thanks for the info i didn't know sir. A laptop i bought from best buy came with windows 8.1 a few years ago and i upgraded it to windows 10 when it was free..is it possible to move windows 10 to my future pc?
No, because it is a prebuilt / OEM laptop and uses OEM Windows which is legally permanently tied to your motherboard. You'll need to purchase a new Windows license to remain legal.
ok thanks for the info