How to find duplicate rows in Excel

You haven't given us much information to work on... Does this array formula help?

Array Formulae are a little different from ordinary formulas in that they MUST be confirmed by pressing CTRL+SHIFT+ENTER to activate the array, not just ENTER.

You will know the array is active when you see curly braces { } appear around the outside of your formula. If you do not CTRL+SHIFT+ENTER you will (almost always) get an error message or an incorrect answer. Press F2 on that cell and try again.

Don't type the curly braces yourself - it won't work...