On our trip last week, my wife (again) dropped her laptop. After that, it stopped working. Oops.
First thoughts were that it was a failed hard drive. All my utilities failed to find it. So I replaced it with a known good drive.
It had a clean install of OS X Lion on it, and was pretty lightly used before I replaced it. I know it was good. The system wouldn’t boot. So I thought maybe that the install didn’t support her older laptop. So out came the Snow Leopard (10.6) install DVD. It failed to install. It found the drive ok, but it couldn’t properly access it. No way to write to it, and diskutility was unable to unmount the drive.
Out it goes, and back into an external case and off to my main mac. No problems, the drive behaves as expected.
Take the original drive and put it into the external case (a generic OWC FW800 enclosure), and bam, the system boots off it fine.
So, it is either in the drive cable (unlikely) or the system Logic Board (much more likely).
Alas, it is beyond my ability to troubleshoot, or repair, so off to Apple for my wife. But I spent about a half a day fiddling with it. Oh well.