The real question is:
WHY are you asking this?
Sadly I also need this question answered ( sorry for digging up old posts ).
I use Blancco wiping software for my job, and just about all the HP model desktops / laptops have their DCO's locked on the HDD, and I get an error from Blancco about it. I've dug around the BIOS the best I could but haven't had any luck with figuring out what option would even correlate to the DCO.