If you want Excel to check if a cell in Excel is NOT equal to something, you can do it in one of two ways.
Use <> to tell Excel not equal to
The first thing you can do is use a less than and bigger than symbol and combine them to create a not equal to. Unfortunately Excel does not allow ≠ (not equal to sign) but by using <> in a formula you are telling Excel the same thing.
As an example you could build an IF that says
“if cell A1 is not equal to 0, then display the word Number otherwise the word Zero”.
Use the NOT function
Another way to achieve the same thing is to use the NOT function.
In this case you can set up a logical test (e.g. A1=0) and tell Excel to do the exact opposite by using the NOT function i.e. NOT(A1=0).
In the IF example above we would therefore enter