How do you unblock things on your computer if it has a safety block and you forgot your password for it? Like going to sertin sights or downlowding things if those things are blocked by my big brother he changed my password how can I un do what he did?

Talk to your mom and dad, and they can make your brother fix it ( assuming it is not suppose to be on it)

No one here would tell a child how to by pass safety on their computer, since we have no idea if it is suppose to be there or not.