Blizzard Entertainment's Battle.net system links all of your Blizzard games through a single account. It's free to sign up for a Battle.net account, and your account keeps a record of your online game purchases and CD keys. You use the same Battle.net email and password when you log in to play Blizzard games online. If you'd like to delete your Battle.net account, you have to contact Blizzard customer services; you can't disable the account on your own. You can contact Blizzard in several ways.