Newly Invisible My Passport Ultra

This is in reference to a new 3-Tb My Passport Ultra operating on a decent HP tower computer in a Win 7 environment over known-good USB 3 cables and ports. It is not visible in the device manager or “disk list.” I have loaded files until a few days ago when it became invisible. I have tried WD’s data lifeguard diagnostics and it is not visible there, either.

However, it is fully visible and operational on a 10-year-old laptop running XP so I think we can presume it is NOT hardware or the physical drive.

So what is it and what is the fix?

I’d replace the USB 3.0 cable with a Micro USB 2.0 cable (It can be used in the 'flat" half of the connector) to force USB 2.0 mode in case there is a driver-controller issue.