Note: Product keys are necessary even if you have a valid serial number, as they identify the specific software package being installed. How to Find Your AutoCAD 2013 Serial Number and Product Key
For the standalone version of the software, the product key is: Serial Number Format product key of autocad 2013
I can provide targeted troubleshooting steps for your situation. Share public link Note: Product keys are necessary even if you
can be a bit of a puzzle, especially when it asks for that specific 5-digit product key. Unlike a serial number, which identifies your specific license, a product key tells the installer exactly which package you are installing (e.g., a standalone version versus part of a suite). which identifies your specific license