That mobo does not support the 2400.
If you had the 2400 'S' model that is supported.
I have a Intel I5-2400 processor installed on asus H61M-CS motherboard. At bios screen it shows an error This CPU is not supported. Press F1 to continue. After pressing F1 everything works properly just sometimes its get lags dont know is it because of my old HDD or what. Is it OK to work with the same processor or do i need to change it. Budget is concerned issue to me. Little tight on budget right now. Any suggestion will really be appreciated please help guys.