Unable to play Minecraft

Hello Mojang, I am having quite a issue with mine craft and in so playing it. When I load it up, the main menu shows up, but when I try to load or create a world it crashes!!! It has really got on my nerves the past week, and I am clueless on what to do? I could use your advice on what is it I need to do to fix it. It says that google. GSon Internal bind tree adapter is the cause of the crash, but im not a programmer and am absolutely confused. I really need your help, so please give me an answer.(also affects 1.7.10)

• DragonFest21