Let’s say your external hard drive failed to start. When you connect your hard drive to a computer nothing happens even though it used to work just fine a while ago. The hard drive appears to be dead or it shows some signs of life but will not appear in My Computer. Is your data gone? Can you recover files? Yes, it’s possible.
There is a good chance that your hard drive is still in a good working condition and your data is safe. It’s likely that the failure is related to the circuit board inside the external enclosure or the power supply.
An external hard drive is nothing more than a regular 2.5″ (laptop) or 3.5″ (desktop) hard drive wrapped up in an external enclosure.
You’ll have to find a way to crack the enclosure case wide open. I cannot provide instructions for any single case out there but it should not be very difficult. Use your brain and a small flat head screwdriver.