mate im useless too im no techie what so ever. once you have removed the 2 screws you really need to give the unit a good yank (dont pull the screen, not that you can as it should be in its closed position).
the best way i can describe to remove it is to put your four fingers inside, where the plastic panel cover has been removed and pull with force towards you pushing your thumb in the opposite direction (pushing towards the air vents). you really do need to give it a good pull, dont be afraid