It seems like there is an issue with the connection between the hard drive and the PCB. Or the hard is dead. If possible you can try to dismantle and try to connect just the hard drive to your internal computer SATA port see if it work. On how to do that, you can search in the forum on how to remove the internal hard drive.
You need both hard drives. The 1st one is your OS “Windows” and the 2nd is your WD drive
Hopefully, when boot in to Windows, it can see and assign a drive letter for it. Best of luck
Thanks for the clarification.
Unfortunately, I don’t have the equipment for this. So combined with the assumed low chance of getting it to run smoothly again it might make the most sense to just throw the drive away.