[FIX] [WD] Internal hard disk not found - Solution

Hi I bought a WD terabyte external HDD (p/n WDBABV0020BBK-00) and it was brilliant for about a month with my Mac but having left it in the drawer for a few weeks it has decided not to exist - i.e. it first of all said it was corrupted then when I plugged it in it is not discoverable. I plugged it in to my PC and it showed so I tried to re-format it accepting that the data I had backed up was lost, but then that stopped working and it is undiscoverable on the PC

I tired downloading the Acronis Disk Director but this can’t see it either.

Help! It was such a fantastic piece of kit, and now it [Deleted]. Such a shame!!

Any ideas?