When i am trying to login to my admin pannel.... once i press login button it again asking the user name and password.... what i have to do
Meaning it doesn't accept your username and password? Are cookies enabled? Confirm from your database whether you are using the correct user name and change the password from there if you want to.
During login if this message is not appear "Incorrect Username/Password". it means that your password or username is not wrong. There is another problem. so u need to reinstall wordpress software on your host