The computer refused to boot with the familiar folder with the? in the middle. This was obviously a bad hard drive right - NOT! OK motherboard right, no. This is tricky to diagnose in that you have to physically remove the hard drive, not a problem on the 2012 MacBook Pro. Drive OK motherboard OK has to be cable and it was. In my many years of fixing other peoples computers this was the first time I had encountered this problem but an easy enough fix and the hard drive was just fine thank God as my mother had not done a back up in 850 days, Jesus! The documents are on iCloud but her photo would've been lost.
Get the unit with everything including the LED. If you have to take stuff apart and put it back it's never the same in my experience. Like the home button on an iPhone 5s just doesn't feel the same when you have to rip it out and put it back in