If you possess a legitimate, legally purchased copy of AutoCAD 2009 and need to install it, here is how you can find the authorized information:
The serial number is typically found on the original product packaging, the CD case, or in the confirmation email sent by Autodesk upon purchase.
Log in to the Autodesk Management Portal . Under the "All Products and Services" tab, you can view details for legacy products assigned to your account.
Q: Can I transfer my AutoCAD 2009 license to a new computer? A: Yes, you can transfer your AutoCAD 2009 license to a new computer by deactivating the software on the old computer and then activating it on the new computer.