Do's

• Check all the connections of the drive (power and data connections).
• If this fails, try connecting the same drive on another working machine.
• If the above measure also fails, confirm whether the controller card is Ok.
• If every above given effort fails, immediately stop working on the drive and contact Unique Data Recovery Specialists.

Don'ts

• Never Hit the hard drive / tap it with a screw driver
• Never Drop/ Heat OR Freeze it. Your hard drive is made up of electronic and magnetic components. Such steps only can aggravate the problem and cause serious damage to the disk and permanent data loss
• If there is a firmware problem, replacement of a defected logic board with a identical one using same firmware version may not solve the problem as some manufactures, in some models and series, record all those parameters in a ROM memory located in the logic board, or a part is recorded in that ROM and another part in an EPROM or some kind of flash memory that's inside the drive. All self experiments only cause further damage.
• Never open the hard disk. Hard disks strictly can be opened in class 100 clean rooms. If you open it anywhere else, you cause further irreversible damage to your disk and invaluable data.