My Passport Essential 500GB showing power light, but not in computer

Hi,
My computer doesn’t show the drive on Disk Management, Explorer, Device Management or Control Panel. I have tried testing the drive on 1 Windows 7 computer and 1 Windows 10 computer but it doesn’t show up regardless. If somebody knows how to fix this issue, thanks.

Info: My Passport Essential WDBAAA5000ABK-00
ASUS Vivobook X202EP 2GB RAM Intel Celeron CPU @ 1.10 GHz (Windows 10)
iMac 21.5" 16GB RAM Intel Core i5-2400S CPU @ 2.50 GHz (Windows 7)

Thanks,
hfymn.