If you have forgotten the email address you used to create your Battle.Net account, you will be unable to play any Blizzard games that require logging in, such as World of Warcraft and StarCraft 2. Having an active Battle.Net account also offers other benefits, such as the chance to receive invitations to the beta testing stage of future game releases and the ability to download copies of all the games you have registered with your account without needing to have the original installation disks on hand. Fortunately, recovering your account is not impossible. You have several ways of determining the email address you used.
Create a list of all the email addresses you have.
Check your e-mail archive for each of your e-mail addresses, looking for any message from Blizzard related to your Battle.Net account. Examples of these messages include server transfers, faction changes and character recustomization for World of Warcraft, any purchases you may have made from the Blizzard Store, including upgrades to your World of Warcraft account and digital game downloads, and invites to previous beta tests.
Test each e-mail address using the Battle.Net password reset feature. From the main Battle.Net website, click on "Log In" to bring up a login screen, then click on the small "Can't log in?" link found under the "Log in" button. Select the first option, "I forgot my Battle.net account password, or am currently locked out of my account." Enter the first e-mail address in your list as well as your first name and last name in the appropriate boxes, then click "Continue." If the email address is not associated to a Battle.Net account, an error message will appear. Repeat the process until you have tested all the email addresses on your list.
Collect as much information as possible that may help specifically identify your Battle.Net account, such as the names and servers of characters on your World of Warcraft account as well as the CD keys for any games associated with your Battle.Net account.
Contact Blizzard's Billing and Account Services department.
If you did not sign up for Battle.Net using your real name and contact information, your Battle.Net account may be permanently unrecoverable.