My son's MBP stopped booting and the Apple store said it was a HD issue, so I bought him a SSD to replace the HD that came with the machine. Low and behold, it wasn't a HD problem. I replaced the HD with the SSD and booted from the Optical drive to reload the OS. The SSD was not seen in the disk utilities. I then put his old HD on an external connector device that allows it to connect via the USB and it was seen fine. In fact we were able to recover the data. I don't want to spend $450 to replace/repair the logic board, so I bought a bracket from OWC that allows the HD or SSD to be installed in the optical drive space. Sorry for the long explanation. Here is my probelm. I can't figure out how to tell the MBP to boot from the drive in the bracket. I put his HD back in to try and boot. I tried the holding the C down during boot. I tried the option key during boot but all I get is a gray screen. Any help would be greatly appreciated.