If Civil 3D 2016 is installed as part of a suite rather than a standalone product, the product key may differ: Infrastructure Design Suite Premium 2016: Infrastructure Design Suite Ultimate 2016: www.cadable.com Where to Find Your Official Information Autodesk Account: Sign in to the Autodesk Management Portal
If you are reinstalling the software and cannot find your serial number, Autodesk allows you to recover it via the "License Recovery" tool on their support site, provided you still have access to the email address used for the original purchase.
From your Autodesk Account, download AutoCAD_Civil_3D_2016_English_64bit_dlm.sfx.exe . Do use a torrent.
If you are installing Civil 3D as part of a larger design suite, the product key will differ: AutoCAD Civil 3D 2016 Infrastructure Design Suite Premium 2016 Infrastructure Design Suite Ultimate 2016 AutoCAD LT Civil Suite 2016 microsolresources.com Autodesk 2016 Product keys - ARKANCE UK Community
Autodesk uses specific product keys to differentiate between software packages. Even if you have a valid serial number, the installation will not proceed without the correct key. 237H1