Disappeared Posts & Unaccepted Admin Login

Suddenly, with no reason, all the posts and pages i have on my blog gone away… I have my theme and plugins, but instead of posts and pages all i have is “Sorry, nothing found.”

I tried to access wp-admin panel, I couldnt because it keeps saying “wrong username”. I can see my admin user and all the posts in phpMyadmin and I add new users; but i cant log-in with them either…

Any ideas?