Open your model in NifSkope and check to make sure that the correct shaders are active. For anything other than skin, the shader type should be sader default. For skin, it should be shader skin. For each item, except for any caps or meat, shader flags that should be active are Specular, Skinned, Windows Environment Mapping, Remapple Textures, Shadow Map, ZBuffer Test. Along with FaceGen if it is any skin part. Also check to ensure that the path to the texture is correct.