Detect individual Hardware GUID number (like punkbuster)

Hello,

i read the news on PunkBuster ( http://www.punkbuster.com/index.php?page=announce.php ) and i saw the new function called 'Detecting individual Hardware GUID' (i think it's the motherboard product number), and storing it in a hashcode so that the computer could be identified with a single hashcode. I found that pretty interesting.

So have you got some ideas how to get an individual hardware GUID hashcode (perhaps motherboard product number) ?

Thanks
Manuel K.