Excel 2007 : Formulas not working properly

I am encountering a strange problem with Excel 2007. Specifically this has to do with the COUNTIF function. What I want to do is count the number of "X" in a row or column. When I type in the formula at the end of the row or column it gives back the correct value. HOWEVER, when I add or delete an "X", the value remains unchanged. Also when I copy the formula using relative references, it generates the correct formula but returns the original value regardless of the number of "X" in the row or column. Am I missing something fundamental here or is my version of Excel glitched?

The problem is not COUNTIF specific. The problem occurs with any formula e.g. SUM

That did the trick! I'm having a hard time navigating around 2007.