cmfriend,
Just about any external HD can be taken apart. Look for some small screws on either end, take them out, and then gently pull the carriage (if there is one) out. Take a look at the connections and make sure they're tight and then try the drive again. If it works then your OK. If not then I'd pull the drive totally out and stick it in a desktop and see if it works there.
Lastly, if this makes no sense to you, then take it to a professional. This would only take me a half hour or so to do so it shouldn't be very expensive. There is a good chance that your data is still OK but the drive case has probably been damaged or a connection has come loose.