make sure that A1 is your active cell, because the formula you
enter is based on the active cell and is applied to all of the selected
cell with appropriate changes in the cell addresses. http://www.mvps.org/dmcritchie/excel/condfmt.htm
Also while mentioning that, might as well mention that the object
of C.F. is to use a formula that produces True or False.
If you don't make sure you have the correct active cell then you
will find C.F. works sometimes and fails miserably other times.
Until you realize how C.F. formulas work.