Can you hear it spin up, or try to spin up?
Have you confirmed that the AC adapter is OK?
Did you drop it?
At the moment it is not clear whether the problem is with your drive or the bridge board in your enclosure. So, if your data are more valuable than your warranty, then you will need to remove the drive from the enclosure and connect it directly to your motherboard. You may want to ask Seagate Tech Support for their OK before you do, though.
