get some recovery software/s and do it yourself (I am not familiar with this). But if the stuffs in the harddrive isn't that important then I would just go ahead and start all over and format the thing.
I might also add that I am not a fan of usb connection for ext. Hdd. I just think they are just too slow for large video files.
Ok so.. I recently purchased a simpledrive 1TB external HDD. When I first hooked it up to my computer through USB, it was automatically recognized, and a few seconds later, I got a message saying that it was installed successfully. So I went on to use it for a couple months, and it worked fine. Earlier today, I wanted to put a couple vids on it, so I opened the folder, and drag and dropped the files (like I've done many times before), and I get a message saying that one of the files could not be copied to the HDD. I didn't think it was that big of a problem, but when I tried to navigate the folders on my HDD, I got a message saying that the files are "unreadable and corrupt". So I tried shutting it off and turning it back on, but when I went to open the HDD folder, a message came up saying that the HDD was not formatted and if I would like to format it.
I was wondering if anyone knew about this problem having happened before, and a possible solution that does not involve reformatting it and losing all my files...

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic