I am having problems with Excel 2007 that I did not encounter in
previous versions of Excel.
Symptoms:

Using statistical functions, such as COUNTIF and SLOPE, the result is
strange: An error message pops up: "Too few arguments" when there are
enough arguments. This happens whether I use the statistical function
generator or type the command directly.

I can take the same worksheet to another computer with a previous
version of Excel and use the commands just fine. When I then take the
worksheet back to the computer with Excel 2007, the cell with the
function command is fine unless I click on the cell -- and then get
the same "Too few arguments".

I am confident that there are not "Too few arguments" when using the
function (I've had many check my work).

This is like a bad joke -- I am a stat nut who can't seem to get Excel
to produce stats.

Any suggestions? I've uninstalled and reinstalled Office 2007 twice
now, with no improvement.