I had that problem before, it started after I messed with the settings, I had to have dolphinnerds.com fix it for me. They are pretty good, I would have them do all your changes for you, but have a long list because they charge $20 for any error fixes (no matter how big or small). If you have a lot you want done for that fee, make sure you tell them, its better to have everything the way you want for that $20.

www.dolphinnerds.com