Hey there, @czglory!
I'm truly sorry to hear about your connectivity issues with the WD My Book external HDD.
I'd strongly recommend you try plugging it to another PC/laptop and see how and if the external will get properly detected there. It's also a good idea to swap the USB cable that is connecting the drive and also try plugging it to other USB ports on your computer. I'd also advise you to check Device Manager and see if it pops up there at least. Make sure you back up as much of the data from the external somewhere else immediately when you gain access to it! Having duplicates of the files on a different storage device/drive is what will prevent any potential data loss.
If none of these work and you are still unable to access it on multiple machines, you should definitely consider contacting our
Data Recovery Partners, if the files are really important to you.
The WD Customer Support could also be able to assist you afterwards, if the WD My Book is still
covered by the limited warranty.
Good luck! Keep me posted with the troubleshooting!
SuperSoph_WD