20 - 30 minuten
Went to boot up my MacBook Pro (Mid 2012) and after a bit it just showed the file folder with a question mark in it, instead of a shiny Apple. It was fine the evening before. Swapping hard drives did not fix the problem, but the laptop booted fine with the hard drive in an external FireWire case. Got online and determined that it might be the cable from the motherboard to the hard drive. It was a slightly popular problem with MacBooks from around this time. Ordered one overnight from iFixit. It arrived the next morning.
A few screws and a little double-sided tape and the laptop was back up and running. It only took about 10 minutes. The cable makes a 90 degree bend when going from the bottom of the DVD drive up the side of the DVD drive, and then again when it gets to the flat bottom of the keyboard assembly that is above the hard drive when it is all put back together. The wiring must break somewhere in those two sharp bends.
I had noticed the laptop "freezing" here and there for several seconds once in a while before the failure. This went on for about two weeks. It may have had something to do with the cable failure. It hasn't happened since the cable was replaced. I don't see any 'wear and tear' on the external surfaces of the old cable, so this would be a bit of a tricky problem to troubleshoot.