My Xbox is locked can u help please?

In order to disable the parental lock on your Xbox console you need to follow the instructions on this Xbox support site.

How to reset forgotten pass code for parental controls on Xbox 360


Basically, in order to prevent smart kids from finding a default reset code and disabling the parental controls without their parent's knowing, each Xbox console has an unique reset code that is calculated from the console's serial number.
So if you are unable to remember your secret question to reset the console yourself, you will have to contact the official Xbox support here:

https://support.xbox.com/contact-us

When you are talking with a support agent, you need to confirm, that you are an adult, and then give them the console serial number.
They will then walk you through the process of unlocking your console.