Trying to copy photos from iPhoto to my hard drive.

I have been trying to copy photos from iPhoto to my hard drive. I have tried opening two Finder windows and dragging the photos and I have tried exporting. Neither works so I'm wondering if there is something wrong with my hard drive. Anyone have any ideas how I can check it's operating ok? if not do you know of another way to copy photos over? No point having a hard drive back up if you can't actually back up!!!
Thanks