Hi,
not that I know anything about pirated licenses but after you uninstalled AutoCAD, did you do the following?
1. Remove C:\Program files\Common\Autodesk Shared?
2. Remove all and each reference to Autodesk from Registry?
3. Reboot and re-reboot the PC?
4. IF you know the hacker/s, did you search for their references in registry/in Program-files? Example: xForce...
Cheers,
Petri