getting started

What happens when you can't seem to get started with writing a new novel? I've been trying to take the plunge since Christmas with a new, shiny novel. I've compiled a list of all the 'short stories' I've written that haven't worked because they were novels  in the making. I've played around with characters and situations from those. I've started to write what I thought was a beginning but somehow it all seems to be lacking in life and the novel stubbornly refuses to grow. I love writing, I love the thrill of the daily word count, I don't have any problem writing when I just have a few moments. So why isn't this one coming to life? Answers on a postcard please...