Originally posted by: Lord Evermore
If the USB enclosure's controller board has failed, then yeah that could make it unusable.
External drives are just standard IDE hard drives connected to an IDE to USB bridge controller. (Though I suppose eventually they might start using SATA drives.) Crack open the casing however you must, and pull it out. As long as the drive itself didn't fail, you should be able to just set the jumper to slave and it'll work.
Of course if there's a warranty on the thing, you might want to get it replaced instead of destroying it.