Then you just go to the website, and login. First you will retrieve your serial number/code. Then, way down at the bottom, after all of the many modules that have been published, there will be a seperate, special section of links for the original DCS: Blackshark (Game of the Year Edition, Extended Edition, Special Edition, 5th year Anniversery Edition, 10 year Anniversery Edition, Gold Edition, and finally, the Francis Ford Coppola Approved Absolute Final Cut Not Releasing Another Version Edition.)
Then you'll just pick one of those and d/load it. After you install it it will ask for your serial number, and you'll be back in business.