Download the media creation tool Run it and choose to upgrade the current pc. After completion of the windows 10 instalation get the (w10) product key with a product key finder. Now with the product key you can run the media creation tool again and choose the 'other pc' option. Choose the language, 32/64 bit and the correct w10. If you want create a bootable USB (minimal a 4gb stick) choose USB flashstation. If you want to create a ISO only choose ISO. You can also download the ISO form Microsoft and use for example Rufus to create a bootable USB. The key from w10 is locked to the current PC (hardware). After upgrade you cant install to other PC. And that is the strange part. If you have a retail windows 7 or 8. You can rebuild your pc (mobo/proc/mem) upgrade and install it again. Seems like with w10 you can't do that. You probably need to call Microsoft support to explain that you upgraded your system.