Your model is affected by Seagate's 7200.11 BSY firmware bug, in which case Seagate is still offering free data recovery.
Otherwise see this thread for an easy DIY fix:http://forums.seagate.com/stx/board/message?board.id=ata_drives&message.id=18467#M18467
See the following bulletin for an explanation of the BSY bug.
Urgent Field Update. Topic: Drive Hang after Power Cycle:http://www.expreview.com/img/topic/seagate_firmware/1-16_KB11_Barracuda_Field_Update.pdf