To activate your AV4 account, go to the AV4 online website at https://av.santillana.es/, select the “Enter” option on the main screen, and then choose “Haven't activated your account yet?” on the next screen. 

To check if your license is already registered, select the option to create an account and enter the license provided to you. Depending on the verification results, the license will either be registered or not, based on the required conditions: 

• Registered license: A message will appear stating, “The provided license is already in use.” 

• Unregistered license: If, after entering the license and user details, an error message saying 'Error registering the license' is displayed, the license is not registered. If entering the password allows you to proceed to fill in your first and last name, the license is unregistered. 

To continue with the account activation process, after verifying the license status, a window will appear where you must enter the license, password, and email address twice. The email address cannot be copied—it must be typed manually to avoid errors during activation. 

Finally, you will receive an email in the inbox of the address you provided during registration (check your “Spam” or junk folder if it is not in your inbox). Click the link in the email to complete the activation, and you will be able to access your account.