If it works as an external I’m taking a wild guess that there’s something up with the partition table. If anything isn’t right with this, the drive won’t boot.
I was saying to put the SSD back in the machine, boot off the lion install disk or whatever came with the computer, and access disk utility through this. Do not try to boot off the actual ssd. If disk utility sees the drive, format and try to set it up again with a GUID partition table and then follow with a fresh OS install.
