my external hard-drive went on the fritz last Christmas. If it's possible, either take it where you bought to get it checked. If your warranty is already up, pop the enclosure and drop the drive into your tower. If it can be read, you're free and clear all you need is a new enclosure. If it can't be read then it might not be working.

Enclosures tend to be delicate and screw up. A friend of mine had theirs dropped onto a concrete floor. You should be okay.

*huggles*