Just put a new Crucial MX300 525GB SSD into the listed computer. Prior to installing it I erased it and formatted it for OS X Journaled (extended) in an external USB enclosure that has its own power supply. Could not get the Mac to see the new SSD to get to Disk Utility on start-up. Thought I messed up the install, so I put the old drive back in and it started fine. Put the SSD back in and still could not get to it from start up. So, I used the enclosure with the old drive via USB and pressed option while starting up. I can see the old drive and Recovery. I click on recovery and after 15 minutes, nothing but a blank grey screen. I re-started and booted into the old drive and I can see the new drive listed as an internal drive. I erased it again and formatted it, but I cannot boot into disc utility when I re-start. I also have an install USB disc of El Capitan and it will not find it on start-up. So, I have a Time Machine back-up that I need to get onto the new internal SSD, but I cannot get the Mac to see it on Start-up. Any ideas...