Dashboard disapeared

Hi,
I´m at my end. After my first website gets a virus waring, my second one has a other problem. The dashboard is gone, after loggin in, i come to the frontend where simply says “nothing found here”.
I was lucky that I made a full backup yesterday, but after trying to upload it cames the message “this database allready exists”.
Well, if my fist site is lost, can anyone please help me to safe the second one? It really seems the apocalypsis for me this week.