Originally Posted by Indigo
If you're getting an "Error Loading Operating System" - you've either got to load an OS on the drive, or set the boot order in your BIOS to the other drive(s) in your system to boot into the OS.
This. If you are adding this drive as a second hard drive you'll need to adjust the boot priority. On older computers with IDE/PATA drives, adding a SATA drive would instantly set the SATA drive to the boot drive and would need to be adjsuted in BIOS. If both drives are SATA, you can either move the current drive to a lower-numbered sata port on the drive to force it to be the priority, or manually change the boot order in BIOS.