I had this EXACT problem and it appeared the render window wasn't loading all the way so I figured the problem was there. I updated my ATI Catalyst drivers to 12.1 (released 1/25/12), rebooted and it started flawlessly!!!! Give it a try guys, update your video card drivers to the newest!\ Edit: Also I had to make a completely clean install of Skyrim, and use JGSME to remove all mods in order to make it work. But with JGSME it's only a couple clicks to reinstall all of them (I'm running around 40 mods).
