i am not able to acccess mt wp admin pannel

I am using word press 4.0 on my website (24 posts) optinux.com till mornning it was working fine. still the site is accesable but am not able to access my admin panel.
it ask for username and password but it does not load.
i checked my internet connection but is is also fine enough.
please help me as soon as possible if any one can..