How to open Acer Timeline 3820 chassis?

Hey!

I have an Acer Timeline 3820TG and want to upgrade my RAM. Underneath there is a hatch marked with a harddrive / memory symbol. The hatch has three screws on the long side and a handle in the middle, which it looks like I'm supposed to open with. In the middle of the hatch there is another screw, as well as in one of the other corners. The other corner doesn't have any screw. See my beautiful drawing here:

x----x----x
|----x----|
x---|

When I unscrew the five screws, they don't come off entirely. As they're loose, they start to "jump back" as if something was holding them back after each rotation. I can't find any other screw (not under the rubber feet neither), so I'm starting to suspect that the computer - however obvious-looking the memory-marked hatch looks like - contains a hidden screw underneath the keyboard aswell. It could also be that I use too little force, but I've bent a few times and I'm too scared to break something.

Anybody who could give me some advice on this, or a useful guide on how to remove the stuck hatch? I've googled half night without any useful results. Thanks beforehand.

 

there are just some clips that hold it down, just pull it to the left and right for a bit and they will all come out loose. try not to pull up too much so you don't bend the metal cover.

 

I had read everywhere how careful you must be when trying to open it, so I thought I was doing something wrong. However, I tried to use more force and managed to get it up, although breaking one of the little plastic clips on the side. Guess it won't matter much since the screws will hold the whole thing in place anyway. Thanks!