when i open my blender a material is applied automatically and i am unable to use the material node editor. The materials tab also appears different than the usual material tab. I am having trouble applying the usual gloss, mix, and other shaders 

[![my current materials tab](https://i.stack.imgur.com/cu0O1.png)](https://i.stack.imgur.com/cu0O1.png)

[![my current materials node editor screen](https://i.stack.imgur.com/FIm9D.png)](https://i.stack.imgur.com/FIm9D.png)

[![previous materials node editor screen](https://i.stack.imgur.com/KPpof.png)](https://i.stack.imgur.com/KPpof.png)