External hard drive not showing up! help

I have a portable 3 tb external hardrive and it will not show up anywhere on my pc. It sound normal and the light is normal. but in some electrical plugs is the light strong for a few seconds and after a while the light dies and the external hard drive stops. :frowning:

I have test it on 3 different macs and on 2 different pc:s and non of them can find the hard drive. I’ve never dropped it.   

My hard drive 

Have you tried checking on the disk utility window?

http://wdc.custhelp.com/app/answers/detail/a_id/866/session/L3RpbWUvMTM1MjMyMjU2Mi9zaWQvNWJ6MWZJYWw%3D

Look the computer can’t find my ecternal hard drive 

Same thing on my Pc

In that case you can try using another USB cable or another power suply, if that doesn’t work then you might need to replace it.