If you've purchased Pinnacle Studio 11, you can find the serial number in the following locations:
Pinnacle Studio 11 is still copyrighted intellectual property owned by (which acquired Pinnacle Systems in 2012). Using a cracked serial number or downloading an ISO from a torrent site constitutes software piracy under the Digital Millennium Copyright Act (DMCA) and similar laws worldwide. Pinnacle Studio 11 Serial Number 11