Granted, whatever you set in Control Panel ends up in the registry anyways.
Here is the registry setting to check, or to turn off Autorun:
A value of 1 means enable autorun (on), while zero means disable autorun.
Another way to disable autoplay would be to block a drive from the Media Change Notification.
If that is the case you would find a dword "NoDriveTypeAutoRun " either in
For the correct values look here