As you are now getting into recovery you place such a drive in a desktop so you can see it all and have no question there is enough power. USB is only 500 milliAamps and a few drives will not start with that in the common USB case.
In parting, drives are cheap. Your time is what you think its worth. I have a nice collection of failed HDDs at the office ready for recycling.
I have had a couple of laptops recently unable to boot, and the hard drive in one case doesn't appear in the BIOS, and in both cases is not recognised by operating systems when trying to run recovery software such as Hirens Boot.
From what I can see it is most likely the hard drive given up, but it also could be power or data cables or their connection to the motherboard and hard drive.
How does one go about checking these when they are well covered by shrouding in the laptop case, or is it just a matter of removing all the casing.
I have a Toshiba satellite C660 and a Lenovo Edge E420 with similar problem.
Cheers

Chowhound
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