Computer is slow and freezes whenever it is loading something

Hi, I have been using my laptop without problems for about 1 year and a half. Recently, about a week ago, it suddently started to be extremely slow and freeze whenever it is loading something. When I open any website, when I open a picture folder, when I open paint or anything else, my computer just start to load slowly and then completly freeze. The only thing i can move is the mouse...