Try the rear USB ports of your PC, as they provide more Voltage
than the Front Ports, that traditionaly can't power devices and yes
I appreciate it is an Externally powered device and sadly External HDDs
can fail (I've had 2 go in 3 years). The best chance of success is to re-connect
it to your Laptop (if possible) as that was the last known device that successfully
connected and worked. Failing all that, they can be sent to data retrieval places that
may have more success. Good Luck and we feel your pain, as there's nothing worse.