Prewriting Activities (AKA, what to do when you don't know what to do)

So I've been prewriting. A lot. Like every day for the last two weeks. I'm not a hardcore plotter by any means, but I definitely like to have an idea of where a story is going when I get started. For me, nothing is harder on my writing morale than finishing the first draft of a story only to realize I made a critical error right in the beginning and that I have to essentially rewrite the whole darn thing. Not revise, but rewrite, which is exactly as it sounds.
This is why I prewrite. I ask myself the "big questions" about the story. Things like what is the villain's motivation for his/her villainy? Where is the story headed? What's the protag's arc?
Well for my current WIP, I've been stuck on one VITAL question for days now. And by stuck, I mean really stuck; the answer just refuses to present itself. So what have I been doing? Sticking with my prewriting activities. Here's a list of some of them:
1.       Read2.       Check email, Twitter, Facebook3.       Write a crappy blog about prewriting4.       Check email, Twitter, Facebook 5.       Brainstorm with pen and paper6.       Research stuff on Wikipedia7.       Check email, Twitter, Facebook8.       Clean House9.       Read10.   Go for a walk/run/ride11.   Check email, Twitter, Facebook 12.   Visit a bookstore13.   Rifle through my pile of research books14.   Brainstorm on paper15.   Read16.   Check email, Twitter, Facebook
You get the picture.
Moral of the story? Prewriting is a vital step of the writing process, but it's not the only step. When you've done all these things a hundred times and then some, it's time to start writing. Sometimes the answers can only be found within the story.
Self-directed Pep Talk over.
Happy Writing!