Why is my WD on but not being seen by my computer?

Why is my WD on but not being seen by my computer?

I have an old My Book Pro II and plugged it in for the first time in awhile. The blue circle light on the devices “spine” lights up and stays on. The machine starts whirring for about 7 seconds then goes quiet. It’s not showing up on my disk utility for Mac. Notes: It’s also plugged into its own outlet. The USB cord was sitting in storage awhile, no physical damage that I see. Is it possible the cord just would stop working regardless of that?