If you've registered your account using a valid e-mail address, you can reset your password using the "Forgot password" option in the login menu. The reset link will be e-mailed to you. If the e-mail is not there and you've even checked the spam folder, please submit a new request and we will help you out!
Please bear in mind, that you cannot change a password to an account if you don't have the access to the e-mail it's been registered under.