|Troubleshooting USB device problems including for flash drives, external drives, memory cards.|
See Response 1:
Check that out first.
The same things apply if you connect the drive via a firewire connection - the firewire port on the computer and the firewire cable must be able to supply 500ma of current to the external enclosure.
You must connect the external power adapter that came with the drive to the external enclosure as well.
Rarely, not all the ports on the back of a desktop case may be able to supply 500ma each.
If you have a desktop computer, Note that I answered a Topic on this site recently where a guy had an external drive, which does require the full 500ma, connected to a port on the back of a desktop case - it would not work properly when a webcam was in the port next to it, but it worked fine when the webcam was unplugged. Ports on the back of a desktop case often have two ports connected to the same USB controller module that are ports one above the other - you could try connecting the cable to one of those and leaving the other un-used.
After you have checked those things out, if you still get "a low beep", where is it coming from ?
If it's coming from the external enclosure, if the external enclosure's circuits are not working properly, it's likely that there's nothing wrong with the hard drive inside the enclosure, unless you have dropped the external drive, and getting a new external enclosure and installing the hard drive in it should allow the external drive to work fine.
You could check the hard drive out before you get another external enclosure by connecting it internally to a desktop computer