MyBook icon not showing, need to safely turn off to test on another computer

Hello,
MyBook was working perfectly on my iMac up until about an hour ago when I ejected the disk, powered it down and tried to plug it into my colleague’s iMac. It would not show up on her computer and her disk is almost full, so I thought I’d move it back to my computer and move some DropBox projects to archive. But when I plugged it back into my computer, the disk icon would not show up.

The disk is spinning, but there is no light. I have tried all the troubleshooting techniques including different ports, accessing Disk Utility, and power cycling my computer. I was going to test it out on my other colleagues computer, but I am unsure as to what is the safest way to remove the disk since there is no icon to drag to the trash.

Any ideas?

As it would for anyone else, It would be a shame if the disk were corrupted or broken after only owning it for 2 months and only trying to safely move it to another computer once. Fingers crossed it works on another computer!

What is the result when you check your My Book on other computer?

The disk will not mount on any of the other Apple computers I have in the office (there are three of them). I also downloaded a data recovery app which does not recognize the disk either.