Ok making a video and having some problem with some of my objects flashing bright and dark, here is a link to a quick vid of the problem (front of the desk)
1st, check to make sure the normals of the object are pointing outwards. Then, see if you have 2 faces occupying the exact same space. Try removing doubles and see if it fixes it. Also, make sure that you didn’t accidently duplicate the model and leave it in the same spot, as this would result in 2 faces occupying the same 3d space.
I’ve seen that when two meshes are nearly perfectly aligned (doubled). Joining them and removing doubles cures the two faces sortalike interferring with one another.