If no one else offers a better suggestion...
Autodesk recommended uninstall/reinstall procedures are as follows
Uninstall: http://usa.autodesk.com/getdoc/id=TS45252
Ensure the user installing/uninstalling and using the product have enough rights to do so (install and reinstall as local administrator):
Unable to run AutoCAD® as a restricted user http://usa.autodesk.com/getdoc/id=TS1055299
More complete .NET fix if you did not go through this procedure before:
http://forums.autodesk.com/t5/Installation-Licensing/NET-Framework-Cleanup-Tool-for-Unhandled-Except...
Download 2010 through 2014 software (if needed):
http://usa.autodesk.com/adsk/servlet/ps/dl/item?siteID=123112&id=21889745&linkID=9240617