I have built a computer before, but i have never seen the inside of my labtop. And i was wondering if it is risky to open it up, and secondly, how to install my own Network Interface Card?
Don't open up your laptop. The structure within is radically different to a desktop, and the only thing that is user accessible are memory and HDD (CPU on some laptops).
Are you trying to install the card into a mini PCI slot? It's most likely taken up anyway.