If you need access to older versions like AutoCAD 2006, consider these legal alternatives:
: Using unauthorized activation codes violates Autodesk's licensing agreements.
: Open the application. On the "Free Trial" or "Product Activation" screen, click Enter Credentials : Type in your Serial Number Product Key
: Choose "Activate the product" and click "Next".
: You can find this on your original product packaging (CD case or box). If the software is still installed on another PC, type ABOUT at the command line to see the serial number.