...
- The Revit 2014 / 2015 installer you've downloaded from Autodesk is corrupt and will not install correctly. Download your Autodesk installers from the "Autodesk-Student" share here: Software Downloads
- You have uninstalled Revit 2014 / 2015 / 2016 and need to reinstall. When you attempt to reinstall Revit 2014 / 2015 / 2016, the installer reports Revit as already being installed, which you know is not true, since you just uninstalled Revit 2014 / 2015 / 2016. You're unable to install Revit 2014 / 2015 / 2016 again.
- Templates and families not installed installed Revit 2014 / 2015 / 2016?
...