If it's like the acer 5733 I just repaired:
You need to remove the all the screws on the back, the ones inside the battery compartment (there was 4 tiny screws in this bit for me) and then take off the hdd/memory cover and remove the hdd and one other black screw, oh and slide out the dvd drive and put it to one side.
Then you flip it over and take out the keyboard (it has some little spring-loaded things holding it in place that you can push back with a flat head screwdriver so it pops out).
Then you take out 8 black screws from under the keyboard.
Then you can take off the cover, but not that back cover, the cover that has the touchpad mouse on it (where the keyboard was fitted into).
Though after typing all this.. just look on youtube. There is bound to be footage of someone opening one of them.