re: be careful with Microsft's update
I ran the update a few days ago, and have had no AutoCAD trouble, but am using very old versions (13 and 14.). What version do you use?
I did start having bizarre mouse trouble, where suddenly the screen acted as if I had clicked everything on it at once and filled up with dialogue windows, but I replaced the mouse with an old one I had laying around, and it seems to work now, so it might have just been a blown mouse.