When you use Facebook to register or login at BrainCert, you won't be able to reset your password. This is how Facebook connect works. Facebook would not allow importing users passwords for security reasons. So, you will not see an option under your account settings to reset your password. If you would like to disable Facebook connect, you would need to logout from BrainCert and then reset your password using this link https://www.braincert.com/Lost-password.
After you finish the password reset process, you can now login using your password instead of Facebook connect.