Hello, I have a question I'm going to buy a PC without any OS. I have an old laptop which runs win 7 and I've signed up for the free upgrade to win 10. I read somewhere that it's possible to download windows 10 from that free upgrade to my laptop, then put it on a USB. Then put the USB in my PC without OS and install that win 10 from the free upgrade on my new PC. I wonder if this is possible? And if it's possible, do I have to fill in the product key of my old laptop's windows 7 at the installation? Thank you for your help.