I ordered a barebones pc because I've never fully built a desktop from the ground up. I just got it today and installed a bunch of parts from my old desktop. I also put my old Hardrive with windows 10 into the new desktop. I've asked a few people and most said that putting the hardrive in the new desktop would boot up properly. Well it didn't. When i start the desktop it says "Reboot and select proper boot device". I've never installed an operating system before and have little knowledge about a boot menu. I can't afford to buy another copy of windows so i need to know if there is a way to reinstall windows off my hardrive.