If you see websites offering "activation codes" or "keygens" for AutoCAD 2007, those are typically:
Are you trying to from an old file, or do you specifically need to run the 2007 version for a certain workflow?
: Open AutoCAD 2007 and click Activate on the product activation screen.
: While your perpetual license remains technically valid for as long as you can keep the software running, you cannot reactivate it if the software is uninstalled or if you move it to a different computer. Operating System Conflicts