It's brutal, but I've found a firm slap on the right hand rest can "unstick" the drive to make it spin up again. Can you hear the drive trying to spin up? If no action I suggest it won't work, but they sometimes need a little coaxing. Since good 2.5" SCSI hard discs are so hard to come across it's a good idea to stockpile some of them for the future.
JB