It's a common problem really, I had it too. Go into your Steam Library and on the left right click Skyrim and select Properties. Then, go to the Local Files tab and click on Verify Integrity of Game Cache. It'll regenerate your .ini so you'll need to make a copy of it or redo changes if you made any.
Then you should be good to go after that, if you have any more problems try the tech and hardware forums.
Yep this will do it, I have had it happen twice to me and Verifying cleaned it up.
Hey folks, a post or two went away - when you have nothing of value to post, then don't post. Simple rule, will help you avoid a warning.