Say goodbye to your warranty!
Take a small paring knife (or something equally as thin and strong, like a flat bobby-pin) and pop off the front panel. The front panel is the one that has the Hitachi LED that lights up.
Remove the 2 screws hidden behind that panel, and slide the top of the enclosure back!
You should now see 6 screws exposed. You'll need to remove all 6! Pull the Hitachi LED gently upward to remove it.**Note: up to this point all the screws are the same, and it shouldn't matter which one gets put back where.
The internal HDD rack should now be able to be removed from the enclosure itself. It has 6 screws on the side (mine were black) that have slightly bigger heads than the previous 10 screws you removed. Remove all 6 of these.
The HDD itself should now pull up and out of the little metal rack, and all that's left to do is gently pull the circuit board from the HDD connectors.
** USE CAUTION, AS THIS CIRCUIT BOARD IS WHAT ALLOWS FOR THE HDD TO BE CONNECTED VIA USB. YOU BREAK IT, YOU HAVE TO GET A NEW ENCLOSURE **