I accidentally typed a "-" sign into an empty cell, and excel is returning the error message "Your formula is incomplete." The only option for this warning is to press the "OK" button; however, when I do this, it immediately brings the message back up again. I can't access any of my other spreadsheets, and the application itself won't quit, either. Any idea on how I can get rid of this message if the button to close it isn't doing anything? Such a small thing is causing all of Excel to have a fit!