Last couple of days ago I installed magento in my localhost to check a theme, but whenever I tried to login admin panel it just says nothing and show me the login page again and again. If I give wrong credentials, then it show me the wrong credential msg but if I give right credentials it just redirect me to the login page without any msg. It was very frustrating. I searched a lot and found that its a session parameter problem. Here is how you can fix this with a very easy step.
1. Go to appcodecoreMageCoreModelSessionAbstract
2. Open the file Varien.php
3. Search call_user_func_array(‘session_set_cookie_params’, $cookieParams); and make it comment like follows,
Bingo!!! Now you can login to your admin panel of localhost magento installation 🙂
This method works for me. Hope it will works for you too.