I've never had this issue before:
I had an OWC ssd in my 2009 macbook pro, and I put it into a 2008 aluminum macbook. It worked perfectly. Then, I took it out and put it back in my macbook pro, but the computer wouldn't start up. It wouldn't even get past the grey screen (not even an apple logo!). Now it won't work in either computer.
I've tried starting up in recovery mode: nada.
I put it in my external HD enclosure and connected it to my macbook air. Nothing is showing up in the disk utility or in disk warrior (and yes, the enclosure works OK, I checked the SATA cable, etc, etc). I'm at a loss for what to do next.