Major problems with sofware and disk

I tried to install windows using bootcamp and it didnt worked so this morning when I turned my system on it was a black screen with a white blinker at the top. I then rebooted and held option button and the only software I could choose was windows. My mac os x has gone!? I then entered the install dvd and no destinations can be found! To top it off I need to do my coursework! Any help would be great!