Texture issues

All the textures of entities are completely black. The textures of all not "glass" block in inventory are also black. And Steve is also transparent. I don't now what to do. I think it's because of my computer. It's too weak for Minecraft. I don't want to quit this grate game on it's greatest update ever. I am so sad now. Please, could you help me somehow?
(Sorry for bad English. It's not my native language.)