so i have recently built a new gaming computer from scratch from buying a new gpu cpu motherboard psu ram and i have took out my hard drive and cd/dvd driver using them in my new build and i must say it works amazing which there fore leaving the other components that are not needed with the old computer and i have decided i wanted to bring my old computer back to life for my brother to use for gaming so i then bought a new cd/dvd driver and a brand new 1tb hard drive which was needed and build the old computer back together but a problem has struck for some reason the computer will not boot with the new hard drive it only allows it to boot using my personal 1tb hard drive that i once used in the computer which i then took out as part of my new build. why will the old computer successfully boot with the hard drive i use and not the new one it will display a message saying CAN NOT BOOT DRIVE TAKING YOU TO THE BIOS or what ever it says. can anyone please help me i would appreciate it thanks