I have had AutoCAD on my lap top for a while. I am using the free student version. I haven't needed it for a couple weeks because of Christmas break and I tried to open it yesterday and it will not open. When I try to open it, the small auto logo screen comes up then AutoCAD opens behind it. At first it has a grey background but before any of the toolbars load it closes. I have tried reinstalling and repairing it and it still does the same thing. please help!