I entered the Windows key, and everything seemed to be going well until I got to: "Where do you want to install Windows?" It shows drive 0 as the SSD and drive 1 as the external drive. I started with the Windows installation with the external USB drive. I had gotten the Windows key off of it before I reformatted it. (I still have the old HD so I can go back to that.) I made the Windows install disk, onto an external USB drive, using Media Creation Tool, I think it is called. So I thought doing a clean install of Windows might fix some of the strange things. I thought the switch might be the problem, so I swapped it out. This one also is strange in that if it is unplugged, it will boot when it is plugged in. It would still show a black screen for 2 minutes or more before showing any of the boot stuff on the screen. Then I cloned the HD to an SSD, figuring that would make it boot faster. I got it running and did some Windows updates. It had an old 150GB SATA 2 HD, upgraded to Windows 10. Two of them wouldn't POST, so I've given up on them. I got six of them running again, and put SSDs in them. The had all been upgraded to Windows 10 2+ years ago. I wanted to try to get them running again. I had taken the CPUs and memory out of them. I have several old computers that had not been used for about 2 years or so. How did you create the install media, if with MCT then good, if another way show us the link. You are trying to install 10 a second time to the same drive? If so you will need to create some unallocated space to install to.