Open Notebook

Hello!

Let me get straight to the problem I face. I have a notebook almost 3 years now. Works almost perfectly fine. The thing is I have very high temperatures.
According to Speccy, i have ~50C at cpu and motherboard. This is not very high, notebook works fine. When I have it powered on for more than 2-3 hours then temperatures get higher, and I also like to watch movies and videos and that makes temps even higher. Yesterday the whole notebook performance dropped dramatically, I checked Speccy and I saw ~75-80C temps. I also have experienced instant shutdowns which i guess are caused by the high temps. I really need to do something. It's summer here but I also don't have money to buy something to cool it. So I decided to open the netbook and try to clean it, maybe dust is stuck somewhere. I can't get to open it at all :mad. I removed all the screws and i try to remove the base but it gets stuck somewhere and im afraid to break it. How the hell do I open it. I have opened many desktop PCs in the past but a never a notebook or a laptop. Any idea? I don't have any guarantee for it and I also don't want to give money for someone to clean it.

The model is Acer Ferrari One 200 series, model no: ZH6. Thanks.