You have a few options. Autodesk provides the following advice:
- How to remove all Autodesk software products from a system to ensure a clean install HERE.
- You are using an AutoCAD® product and you want to know if you should install the latest Service Pack or Update. You also want to know how the Service Pack or Update should be applied. Click HERE.
- Error on startup or AutoCAD is not installed properly? Please reinstall? Try this solution posted HERE.
- Remove any unwanted program and all traces (as well as Windows Registry entries) easily with the freeware Revo Uninstaller. Buy the Pro version if you need more add-in features. There is even a Portable version that requires no installation at all (use it from a thumb-drive).
- CCLeaner is another freeware that is very good at optimizing Windows and is one of the few Windows Registry cleaners that does not harm AutoCAD/LT's installation if you need to use that ability.