Originally Posted by Hikari
I don't have power supply, it only works with the USB ports.
FYI, 2.5" drives don't require any extra power, they get all they need from the USB port.
Only 3.5" drives need supplementary power as the USB port can't supply enough.
This power can either be built-in to the external drive, or in the form of an extra power pack.
Anyway, it sounds pretty obvious by now.
If you've tried it in 3 different, and otherwise OK PC's, then it's almost certain to be the drive, or it's electronics.
If it's easy to take apart, you can buy external enclosures you can put the drive in.
Or if the drive has the same connector as your motherboard, try it as in internal drive. (There's no difference between external and internal drives apart from the enclosure and power supply).
Only do this if you're comfortable doing so, and have basic competence.
The drive is only 4 months old?
If that's the case, the first thing I would do is send it back for warranty if applicable?
One quick thing to try is to see if you can access the drive in Disk Management.
Start, run and type in compmgmt.msc /s then OK.
Under Storage, highlight Disk Management, then on the right-hand side see if the drive is visible and accessible.