iMovie won't load

Hi, I have been using iMovie on my iMac since I purchased it at the end of 2011 with no problems up until now. It won't load (colourful circle keeps spinning - sorry don't know the proper term for this!) and the screen is frozen and won't let me do anything, the only way I can exit is by force quitting, so I can't even send a eport to apple. I can't see any of my projects, the IMovie backdrop is just a blank template. ILife came already installed on my iMac. I haven't used time machine so don't think my movies are backed up on that. I'm not too devastated if I've lost my previous projects as I have them all on DVD, I just need to be able to access and work iMovie to start a new project. Any help would be great! Many thanks 🙂