Did you formated the Hard disk on a Mac? using what file system? cos the macOS file system is not seen on a pc file system and you should use fat or fat 32 to be seen in both systems.
If the hardware is OK ( try a pen drive or another Usb device on the same port to check that its ok.
check the control panel in system- device manager- Ubs devices to see if you recognize the external device you attached. i its ok, then probably the file system that you formated the external HD is not recognized by the pc(laptop) so formar again using Fat or fat32. it must work