Não consigo remover a senha parental [I can't remove the parental password]

If the original owner does not remember the code, you will need to contact
Xbox Live Support. Explain the situation and tell them that you would like to factory-reset the Xbox 360 console. They may need some additional information, but they should provide a sequence of controller keys that will command the console to restore factory
default settings.

Translating to Portuguese using bing.com/translate:

Se o proprietário original não se lembrar do código, você precisará entrar em contato com o
Xbox Live Support. Explique a situação e diga a eles que você gostaria de redefinir o console Xbox 360. Eles podem precisar de algumas informações adicionais, mas devem fornecer
uma sequência de chaves do controlador que comandarão o console para restaurar as configurações padrão de fábrica.

Sorry to hear it. If you're unable to remove the password then I'm afraid that you'll need to do a factory reset on the console. This is the best option anyway as selling a console with games installed is considered Marketplace Theft and could result
in the console being banned from live. Not to mention the other person could decide to get a new console and set it as Home denying you access to those games anyway

Nao consigo tira senha parental

-[Translation - I can't get parental password]

Hello Gabriel,

Thank you for posting on the Xbox forums. We will be locking this thread due to it being revived by a new post. If there are any questions, discussions or issues that anyone would like to bring to our attention, please create a new thread. We will be
more than happy to answer any questions or provide solutions for any issues. Thank you again and happy gaming
Gabriel!

Sinto muito, mas pode explicar um pouco melhor, por favor.

[Translation - I'm sorry, but can you explain a little better, please.]