there's no sign of the drive in disk management (screenshot attached) and I believe the volume letter is M:
as far as I'm aware, it shows in the device manager when its connected via USB. although I'll have to put the drive back in the housing to double check. thanks for the links, I'll check them out. however I'm starting to lose hope...
I was installing Battlefield 3 game at the time. I clicked on the recycle bin to empty it, which is when the drive stopped working.