Conditional Formatting not working?

does the cell Z25 change to an X and and O correctly ?

you would needtwo conditions in the format
one for red and one for green

so as a formula

=Y25=AA25 - RED
=Y25<>AA25 - Green

or as i posted

your original formula in
Z25 was
=IF(Y25<>AA25,"O","X") -
which is different

=Y25=AA25 - Green - "X"
=Y25<>AA25 - Red - "O"

I have added a spreadsheet - which uses the value in Z25 as an O or as an X to conditional format and change colour