If you get the case open, you'll see that it is, in fact, just a regular old internal HD in there. Just install it in your PC as any other HD.
BTW, how do you know that it's the case electronics that are bad and not the HD?
I don't know about that particular model of external drive, but I imagine that the case screws together somehow. Note that manufacturers sometimes hide screwholes underneath stickers or the rubber feet.