I have a 1000GB external hard drive (Seagate 1000GB SATA-2 7200 RPm) attached to an IMicro SATA 3.5" to USB Enclosure. The device has been working for about 8 months, but now when I connect it to my computer it no longer recognizes it. I tried connecting it to my laptop as well, and it doesn't work there either (although I had never connected it to my laptop). I can see a green LED light on the enclosure, and it uses an external power source. I have disconnected all other USB devices as well. It doesn't show up in the Device Manager->Disk Manager.
What could be the problem? Is it possible that the enclosure doesn't work, but the hard drive is fine? If the hard drive failed somehow, wouldn't the computer still recognize a USB device of some sorts? Or maybe the USB cable has somehow gone bad?
If that fails, you can pull the drive out and attach it inside your PC. If the disk works, the Enclosure is broken. If not, the Enclosure may still work but the disk is gone.
As a matter of fact, it is. It says Barracuda 7200.11 on the drive. But unfortunately, it didn't have any firmware updates.
HOWEVER... As I had taken apart the external enclosure, I saw that the drive was not completely plugged in. You don't say! Turns out it was the easiest problem to fix... plug it in.