I have got a problem with rendering a model. There are diagonal lines all over the walls and extrudes when I select 'draw edges' in OpenGL and as I rotate the model little triangles appear all around the windows and various other parts of the model - extrudes, walls, etc. I have installed the latest service pack, re-started, etc. None of my other models are behaving like this and I really need to fix it. All suggestions gratefully received.
There are a couple of files attached illustrating my problem.
Cherry Tree Cottage - Model - 2.pdf
Cherry Tree Cottage - Model.pdf