Some years ago my hard drive was acting up and wouldn't boot, so I went and bought a new one. I just plugged in the new one without removing the old one and installed windows on it. Once I was in I realised all my files were still accessible on the old drive, which was great. I copied them over and then I removed the old drive and tried to boot, it said it couldn't detect a boot device. I plugged it back in and it worked fine, so that's how I'd been using my computer for the last few years. Today, my computer just restarted itself and I got a message like AHCI port 2 device error and also disk read failure, on the old hard drive. I tried restarting a couple times and manually selecting to boot from the new hard drive in the bios but same thing. I tried to take out the old one but I got that same mesage I got years ago about not detecting a boot device. Not really sure what to do at this point other than going out and buying a new drive, reinstalling windows and just copying over all my stuff from the working hard drive and getting rid of both of them, but I would appreciate a cheaper solution.