If you have trouble with AutoCAD and uninstall it and reinstall it, you may still be getting the same errors and wondering why. This is because uninstalling AutoCAD does not remove all the 'crumbs' left behind. These crumbs can get in the way of a good AutoCAD reinstall.
There are a number of pages on Autodesk's Knowledge Base that deal with this, many of them redundant. Here is the best one I have found:
Remove Autodesk Software (Windows)
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