This may or may not be your problem. But one common error made is opening the page by double clicking the file.

For example, if the page you want on the website is index.php sometimes people try to use it by double clicking it to open it in the browser, however this usually opens it as a file, not as a web page, which can break some code, especially php elements(such as login forms).

So as best practice always make sure that if you're gong to the local index.php to use it as a live local site, input the url into your browser, do not open the file directly(the url would likely be something like http://localhost/index.php or even just http://localhost/ ).

So if you've been trying to use the page by clicking the file, try doing it this way instead and see if that helps.

Are you able to get to the login page? If so, you can use the "forgot your password" section. Enter your email address and click "reset and email password." Since you probably don't have email setup, you will need to access your database ( perhaps through localhost/phpmyadmin/ ) to see the body of the message. Copy the reset URL into your browser and you should be able to reset your password from there.

I originally found this here:

http://www.concrete5.org/community/forums/usage/reset-my-password-o...