You should check the cables to make sure that nothing has come loose. Also try one of the free partition managers (Paragon, for example) to see if they can see and partition the drive. If that fails then I would suggest a faulty cable, motherboard port or drive. The first two can be eliminated by substitution; in the third case you will need to RMA the drive.
Keep a careful note of any error messages, recording the exact wording. It's difficult, or impossible, to trace "something like" messages.