My Excel has stopped responding to formula changes. I have a workbook that is set up with multiple spreadsheets, and up until this morning, everything was working fine (the cells that are supposed to auto-populate/change did so as expected). Now, when I changed some of the formulas (basic SUM, COUNT, etc. formulas), the cell that's supposed to show the answer does not show the new value, and the corresponding cell on subsequent spreadsheets do not change. When I re-entered the formula, the new value shows "0". I checked other Excel files, and now they are not responding as well.
I've already checked Tools<Options<Calculation<Automatic. Did I hit a button that made the whole thing go haywire? Help!
OS: Windows 7 Home Premium 64-bit