Why i couldn't log in into my facebook accoun

Hello,
i couldn't log in into my facebook account since last week. however,i can open other browsers such as youtube,msn and twitter. When i'm using my friend's laptop and login into my facebook account,it works! But when i'm using my own computer to login,the page will display "could not connect to facebook.com". So,what should I do in order for me login into my account again?

thanks,
vana