This recently happened to me, a bought a Core 250 Gig Drive last year and archived loads of music & photo's. When I recently accessed to get some pics it showed up in My Computer but when I tried to open it, it said this drive needs formatting !!!!.
I had being recommended this software Recuva a while ago which I used to recover the contains of my Desktop PC's hard drive which crashed on me and would not boot up
So it's come to my resuce twice simply the best file recovery software I've used.
If you decide to use this and want further instructions give me a shout as sometimes the faulty drive doesn't show so you can't see the contents to recover it, this happened to both of my drives, I figured out another way to get to see the drive contents, once you can see the contents you you just right click and choose recover and a browse box appears simply choose a location to recover.
If it's not in a caddy, you might need to buy one to make life easy or you can simply buy the power suppy and connenting leads if it's one off,I bought both a while ago and they have come in handy several timesLeads Caddy Kit
I've mocked up a screen shot to show it in action.RECUVA SCREEN SGOT
, on Flickr