Revit Services & Support - Revit appears already installed in Windows Control Panel, even after a Clean Uninstall
You already followed these steps for a Clean Uninstallation
Erase the following 3 registry keys. This will indicate Revit has been uninstalled to Windows Installer:
Autodesk Revit Architecture 2013 English:
Autodesk Revit Structure 2013 English:
Autodesk Revit MEP 2013 English:
Autodesk Revit 2013 English:
Autodesk Revit Architecture 2012 English:
Autodesk Revit Structure 2012 English:
Autodesk Revit MEP 2012 English:
Autodesk Revit Architecture 2011 English:
Autodesk Revit Structure 2011 English:
Autodesk Revit MEP 2011 English:
Product IDs for Revit 2012 Products will typically start with 0A4..... You can verify that it is the right key, or adapt to localized versions, by expanding HKEY_CLASSES_ROOT\Installer\Products\<Product ID> and checking the Product Name field.
Warning! Problems caused by improperly editing the Windows registry could render your computer operating system unusable. Microsoft provides a wealth of critical information that you need to know about the registry in the Microsoft Knowledge Base at http://support.microsoft.com.
Use the Microsoft® Registry Editor only at your own risk and only after backing up the registry as well as the system.dat and user.dat files as outlined for your operating system in the Microsoft Knowledge Base and in the related solution, TS66513. Additional information about the registry is also contained in the Help topics in the Microsoft Registry Editor.