Autocad 2006 Portable -

The term "portable" in this context refers to a version of the software that does not require a formal installation process. For engineers and students in the mid-2000s, this provided several advantages: AutoCAD System Requirements: What Your PC or Mac Needs

If you need to use an older version of AutoCAD or run it on a modern machine, consider these official and safe methods: autocad 2006 portable