You need the crack first.(Check at bottom for link).
The Serial number is:
For Nero 10.6 HD PLATINUM:
1)For MP3Pro Plug-In:
But this serial number works.
Please if your a nOOb don't go to Nero with the following serial with any complaints,the key isn't blocked yet and please let it stay that way.
I found this key after downloading countless versions that claimed that they were the "cracked version of Nero".
So it took Me weeks to find this,but it takes only seconds to say thanks.
EDIT:NEW CRACK LINK
It contains instructions in the archive itself.
Link for the crack: