So you can make sure you will be able to play the beta for Black Ops when it comes out. Because the number of people who will be able to play it, is limited.
It is as simple as hitting the Generate! button and the program will do the rest for you. It will contact the Call of Duty Black Ops 2 server and grab a random code for you.
If you are having problems downloading the file you might want to check out the Download Help section.