Recently purchased a new Windows 8 PC. It came with one hard drive. I want to a second hard drive to it. This second hard drive is my data hard drive from my previous computer. However, I have run into issues when the system accesses it. The drive is found in the BIOS. But is not seen by Explorer or Disk Management. I have added the drive to the next available SATA slot: SATA 2. The machine is a UEFI/ACHI based machine. In my reading I have found people documenting the following: 1) adding multiple partitioned hard drives (like mine is) to UEFI based machines is not possible 2) I have seen it suggested that you can only add blank hard drives to UEFI based machines. However, in doing so, I did not have success. I tried to add it as a hard drive with unallocated space and then as a hard drive with a single simple partition. Both attempts failed. My ultimate question: What is the proper procedure for adding a second hard drive to a UEFI/ACHI machine? I do not want to reinstall the OS and start from scratch as I have seen suggested elsewhere. There has to be a way to accomplish this without all that hassle. Thanks in advance for your help.