Is it usb powered, or does it have a mains supply?
If usb powered, has he tried a double usb lead - two plugs to computer, one to drive? I bought an external blu-ray drive that won't work without one, even though it arrived with a single lead. USB has a maximum current per plug.
If it has a mains lead, has he tried a different one?
As the chap form Radio Shack may or may not know what he is doing, I'd suggest that if your friend has a pc - as opposed to laptop - take the drive out of it's case and connect to the main board with sata/ide lead.
If that doesn't work, buy an identical secondhand drive and swap the circuit boards over. Done that three times, successfully.
Thereafter, it's specialist time and about £300.