After a number of failed login attempts, Apple automatically disables an iTunes account. Even if you guess the correct password and log in, you will be unable to perform important actions such as updating your account, changing your password or purchasing music from the iTunes store. Disabled iTunes accounts can be reactivated by performing a security reset at the Apple website.
Open your preferred Web browser and visit iforgot.apple.com.
Type your Apple ID in the field, and then click the blue "Next" button.
Choose whether you would like to authenticate by your account's e-mail address or by answering the account's security questions. Select your option, and then click "Next."
Proceed through the security question dialogs. You will be prompted with information supplied at signup, such as your birthday and first school. Click "Next" after answering both, and then type your new password twice to reset and automatically reactivate your iTunes account. If you chose to use e-mail authentication, click the link in the inbox of the account associated with your Apple ID and provide a new password to reset and reactivate the account.
Open iTunes and visit the store. Your account will no longer be listed as disabled.