with windows 1155 build for windows 10 you can now use windows 8/7 code to register a clean install of windows 10. you can use window media creation tool to make a new bootable 8g usb stick of both windows 10 32 and 64 bit. then boot your new pc from the new iso usb stick and then use your windows 7/8 code. i paid a little more ande i got my dad new rig the retail of windows 10 on a usb stick. oem is good for one pc and one mb if the mb fails or you swap out to many parts you have to contact ms for a new code to reactiate windows 10.