Storejet Transcend offline and unallocated in disk management

Hello,

My hard drive did not appear in My Computer. But I can eject it at icon at the bottom. When I checked disk management, its found out the disk did not listed at the top but listed at the bottom as Disk 2 Unknown 931.5 GB Offline. At the right side it write 'unallocated'. If right clicked at disk management, only Properties and Help can be clicked. If I clicked 'online', its say "The request is not supported".

Actually this happened after I tried following below methods. I tried the method by deleting something at the registry from previous tread and change the drive letter and path..but it does not worked. At device manager, the hard drive can be found under 'disk drive' but not in 'universal serial bus controllers', so I cant follow with that method.

Before this, the hard drive appear at My Computer but Auto-run did not open, and I cant's access the drive.

Please help me :(