So I'm trying to fix my buddy's laptop. He kept getting the error "Reboot and select proper Boot Device." Went into BIOS and selected proper drive. Still didn't work. Tried repairing windows, didn't work. Tried clean install, and it keeps failing. I've deleted all partitions, reformatted, etc. I took out the drive and put it in my desktop, as a slave. It's recognizing his drive after I boot from my SSD, and I can open it and see all installation folders, so it isn't just dead. It will not boot from his HDD in my PC. What am I missing? I've tried both windows 8.1 and windows 10.