During logging, when we tick mark "remember me", browser save this logging info in encrypted form in text file know as cookie.
There is another feature of browser which called "saved login" or "autosave password". During entering user ID and password, browser show message for saving it. If we click remember then these information will be save in browser database and can be seen by anyone, who use your system until we protect database with master key.
Clear all cookies, delete all browsing history, remove any saved password from browser, then try again from clicking ForgotPassword, under Forgot log in info, type your email address and reset your password.
If still unsuccessful, try another browser. Hope you will be able to change password.