|USB devices may not work correctly when they're connected to certain USB ports, e.g. ports in a hub or on the front of a desktop case.|
See response 3 in this:
If you DO have it plugged into a USB port it should work in according to that....
If it's like my various ones, it only lights up when it's being accessed - e.g. while the computer is booting when it's already plugged in, when it's first plugged in, or when you click on it's drive letter.
If it isn't lighting up in those circumstances, it's a lot more likely it's data is damaged than it's physically no good.
Have you been clicking on the Safely Remove icon in your task bar and choosing to STOP allowing access to it whenever you want to unplug it while you're in Windows?
(You can unplug it at any time when the computer is not running.)
In Vista it's a mid green circle - sometimes you may need to click on the < at the left end of the taskbar icons lower right to reveal it.
If you haven't been doing that, it's data is probably damaged.
Some suggestions supplied by aegis1 from a previous Topic
No harm in trying a file recovery program. Depending on the amount of corruption, they can recover data with both FATs bad.
PC Inspector (freeware)
Zero assumption Recovery
The demo is limited
It will only recover 'up to' four folders per run
But you can make multiple runs
Really good, but you have to pay for it.