Who stole my creativity?

Seriously. Where did it go? I have all of these wonderful ideas for my screenplay and I can't for the life of me get them down onto paper. I have tried several times within the past month to sit down and work on it and I can't. I just stare at my computer screen blankly. ARGH. I can see how I want things to be in my head, but they just can't get onto my computer. I feel like I'm drained. I've got nothing.